There needs to be some kind of check.

Just yesterday I was running Copperbell (hard) for my book. 2 wipes on first boss. 2 wipes on second. 4 wipes on last boss before I abandoned. Ran out of stones to feet the worm and the boss was at 30-40% HP. Tank was fine. Dropping the stones was... OK. But there was just a HUGE lack of DPS. After 4th wipe and 20 min left I did vote abandon. Tank protested saying "Oh come on we almost have it!". No... you didn't. 4 times and each time we ran out of stones to feed and boss wasent much below 50%.

I remember how bad things were when Copperbell and Mannor (Hard) came out. The tons of failed runs because of severely under equiped DPS getting into these runs because of SE's inability to calculate iLVL requirements properly.

I fully agree with Marxam. There needs to be some kind of forced check.