Eldritch_Lord
Adventurer
Wouldn't an infinite PP trick be about as obvious/not obvious? It's not like there are spells and feats that immediately cry out "You can get infinite PP when you combine these!"
You have to research those tricks, and if a DM doesn't notice that Nightmares will cause problems, he probably won't also notice when you sneak a Torc of Power Preservation* into your character's equipment sheet.
Incidentally, arcane magic has infinite loops too. Usually involving Sanctum Spell and/or Repeat Spell + Echoing Spell.
It's not a matter of one being perfectly obvious and one being obscure, but there's a noticeable trend for magic tricks to be more obscure/complex whereas psionics ones are relatively straightforward. There's a difference between the following:
"Hey DM, can I take Earth Power?"
"What's it do?"
"Reduces PP spent while on the ground by 1 per power."
"Okay."
"Hey DM, can I buy a torc of power preservation?"
"What's it do?"
"Reduces PP spent by 1 per power."
"Okay."
"Hey DM, can I learn bestow power?"
"What's it do?"
"Lets you pay 3 PP to get 2 PP."
"...hold on a second."
vs.
"Hey DM, can I planar bind a nightmare?"
"What's it do?"
"It's a CR 5 evil flying horse."
"Okay."
"Thanks. Now I astral project everywhere."
"...crap."
Granted, it's not usually that clear-cut, and the example with the nightmare can be avoided if the DM reads its stat block completely and not just HD/CR, but a lot of arcane tricks involve binding monsters for SLAs, stacking metamagic and/or mucking around with spell levels, abusing PrCs for 100+% shadow reality, and stuff like that; most of the time, a component for a psionic trick does exactly what it says on the tin--if you have an ability that reduces PP cost and an ability that grants PP, it's more obvious what you're going to do, whereas Sanctum Spell doesn't scream "stick 5th level spells in wands" or similar.