I think sundering is only dangerous to people who are stuck in a 2e mindset.
"This is my weapon. This is my BEST weapon. This is My Only Good Weapon. If I don't have This Weapon, I am NoThInG."
Here's the way it works:
One of them gets an alchemical silver longsword. It's pretty nice, does +2 damage against lycanthropes. The campaign is focusing on lycanthropes at the moment, so she likes it a lot.
She got some cash, and took it to have it enchanted to +1.
Later on, they found a +1 shortsword. "Feh. I already have one of those... in fact, I have a better one." She sells it, and uses that cash, and some other, to enchant the longsword to +2.
Then what happens when the +2 alchemical silver longsword gets sundered/disjoined or otherwise lost?
"Hey! That's not fair! That was my only good weapon, and now I'm worthless! I can't do anything because YOU destroyed it! It's all YOUR fault, you ruthless, evil, conniving DM!"
Whose fault is it REALLY?