I thought it was, Camarath. Darned if I can find it right now, though.
EDIT:
It comes from this statement: "Spells of the prohibited school or schools are not available to the wizard."
There's really no other way to parse that then, "... are no longer considered to be on his or her class spell list."
Otherwise, it could be taken to mean something like, "Whenever a specialist wizard goes into a store, shopkeepers refuse to sell him MM scrolls."
EDIT:
Sorry - I had to do it.
[sblock]
WIZARD: Good Morning.
SHOPKEEPER: Good morning, sir. Welcome to the National Spell Emporium.
W: Ah, thank you my good man.
SK: What can I do for you, sir?
W: Well, I was, uh, sitting in the public laboratory on Thurmond Street just now, skimming through Ars Maleficarum by Hazrad the Mad, and I suddenly felt the need to end something’s physical existence.
SK: End something’s physical existence, sir?
W: Yes, to blast the very soul from the body of my enemy.
SK: Eh?
W: (In a broad Yorkshire accent) Eee, I wanna kill somethin’, like.
SK: Ah, violent.
W: In a nutshell. And I thought to myself, 'a little bolt of force will do the trick'. So I curtailed my maleficient activites, sallied forth, and infiltrated your place of purveyance to negotiate the vending of some arcane darts.
SK: Come again?
W: I want to buy Magic Missile.
SK: Oh, I thought you were complaining about the bouzouki player.
W: Oh, heaven forbid. I am one who delights in all manifestations of the Terpsichorean muse.
SK: Sorry?
W: (In a broad Yorkshire accent) Ooo, I like a nice tune - you're forced to.
SK: So he can go on playing, can he?
W: Most certainly. Now then, a scroll of Magic Missile please, my good man.
SK: Certainly, sir. What tradition would you like?
W: Well, eh, how about a little Harper’s Best?
SK: I'm afraid we're fresh out of Harper’s Best, sir.
W: Oh never mind, how are you on Tenser?
SK: I'm afraid we never have that at the end of the week, sir. We get it fresh on Monday.
W: Tish tish. No matter. Well, stout yeoman, four scrolls of Majere, if you please.
SK: Ah. It's been on order, sir, for two weeks. I was expecting it this morning.
W: It's not my lucky day, is it? Er, Bes Pelargic?
SK: Sorry, sir.
W: Red Wizard?
SK: Normally, sir, yes. Today the griffon broke down.
W: Ah. Rary?
SK: Sorry.
W: Elementalist? Mordenkainen?
SK: No.
W: Any Waterdhavian Blackstaff, per chance?
SK: No.
W: Lilliputian?
SK: No.
W: Elven high magic?
SK: No.
W: White Silverymoon?
SK: No.
W: Sharn Blue?
SK: No.
W: Twinned?
SK: ..... No.
W: Cat-wizard of Chuult?
SK: No.
W: Blue Wizard?
SK: No.
W: Bree, Rockhome, Freeport, Kingsport, Savant, Saint Talia of Mystra, Caramon, Belgarath, Belgarion?
SK: No.
W: Alustriel, perhaps?
SK: Ah! We have a scroll from Alustriel, yes sir.
W: You do! Excellent.
SK: Yes, sir. It's, ah ..... it's a bit draconic.
W: Oh, I like it draconic.
SK: Well, it's very draconic, actually, sir.
W: No matter. Fetch hither le scroll de la Belle de Silverymoon! M-mmm!
SK: I think it's a bit more draconic than you'll like it, sir.
W: I don't care how darn runny it is. Hand it over with all speed.
SK: Oh .....
W: What now?
SK: The cat's cast it.
W: Has he?
SK: She, sir.
(pause)
W: Gord?
SK: No.
W: Elminster?
SK: No.
W: Cabalistic?
SK: No.
W: Vaasa spirit shaman?
SK: No.
W: Kara-turan carved scrolls?
SK: No, sir.
W: You do have some Magic Missile scrolls, do you?
SK: Of course, sir. It's a scroll shop, sir. We've got .....
W: No, no, don't tell me. I'm keen to guess.
SK: Fair enough.
W: Er, Merlin?
SK: Yes?
W: Ah, well, I'll have one of those.
SK: Oh, I thought you were talking to me, sir. Mr Merlin, that's my name.
(pause)
W: Mulhorand?
SK: Ah, not as such.
W: Er, Gorgon-blood?
SK: No.
W: Aundair?
SK: No.
W: Tenser?
SK: No.
W: Blipdoolploop?
SK: No.
W: Sigilian Fated?
SK: No.
W: Karnnathi skeleton-mage?
SK: No.
W: Xendriki lizardfolk?
SK: Not today, sir, no.
(pause)
W: Ah, how about WotC Standard?
SK: Well, we don't get much call for it around here, sir.
W: Not much ca- It's the single most popular spell in the world!
SK: Not round here, sir.
W: And what is the most popular spell round here?
SK: Illefarn, sir.
W: Is it.
SK: Oh yes, sir. It's staggeringly popular in this manor, squire.
W: Is it.
SK: It's our number-one best seller, sir.
W: I see. Ah, Illefarn, eh?
SK: Right, sir.
W: All right. Okay. Have you got any, he asked expecting the answer no?
SK: I'll have a look, sir ..... nnnnnnooooooooo.
W: It's not much of a scroll shop, is it?
SK: Finest in the district, sir.
W: Explain the logic underlying that conclusion, please.
SK: Well, it's so clean, sir.
W: It's certainly uncontaminated by scrolls.
SK: You haven't asked me about Alaundo, sir.
W: Is it worth it?
SK: Could be.
W: Have you- SHUT THAT BLOODY BOUZOUKI UP!
SK: (To dancers) Told you so.
W: Have you got any Alaundo?
SK: No.
W: That figures. Predictable really, I suppose. It was an act of purest optimism to have posed the question in the first place. Tell me:
SK: Yes, sir?
W: Have you in fact got any scrolls here at all?
SK: Yes, sir.
W: Really?
(pause)
SK: No. Not really, sir.
W: You haven't.
SK: No, sir, not a scrap. I was deliberately wasting your time, sir.
W: Well, I'm sorry, but I'm going to have to summon a demon into your pants.
SK: Right-O, sir.
W: (Summons demon) What a senseless waste of human life.[/sblock]