Falkus
Explorer
If the dummies learn to post guards while they sleep, it's not a waste of those sessions. Unless a DM is just out to kill the party, I'm of the opinion that they got the TPK they deserved. Let 'em cry.
It was a bloody inn where they had absolutely no reason to suspect they were in danger, not the dungeon of horrendous doom. If they were knew somebody was after them, then a guard would be a reasonable precaution, but if not, then it's just bloody paranoia. If your players are paranoid to the point where they always act as if they're in mortal danger, then something is wrong.