^^
With how well my parts have stuck in the past, I wouldn't want to try this. The extruder would have smashed well and truly before the part came off the bed. Almost need to have a failsafe system with a spring and a limit switch. If the part doesn't come off the bed with x amount of force, the spring compresses and the limit switch is touched causing the "sweep" to abort and flag an error to the user in the software.
I too had the same concern as the OP, especially if the software/printer crashed meaning the the extruder head had stopped on the part, continuing to heat it until it burnt. So far I have found that even on a crash the heating process is stopped so I just end up with a dark cigarette style burn were the extruder was (before it cooled). Not much of an issue. Maybe a crash leads to loss of connection, leads to the whole process being killed. A print that comes off the bed before it is finished leads to spaghetti fluff all over the place.
Though coming home to a smouldering house still worries me. I don't want my soliwidow to have more of a reason to hate the 3D printer.