Thanks for the reply Torley and Andrew.
I don't think I'll bother starting a war/thread over this issue because the outcome isn't going to be of any use to me. I'll just have to change the problematic objects into permanent ones and use a timer to delete them.
I do understand why you've had to put restrictions on the temp on rez objects, although I personally would've set the limit for temporary objects to the parcel's prim limit.
Other related problems:
The temporary status of an object now becomes effective the moment we tick the 'Temporary' check box. Previous to 1.11, the temporary status became active after the object was rezzed (temp on rez). Somebody may spend a few hours creating an object, then sets their object to 'Temporary', only to see the object instantly deleted before they even have chance to take it into their inventory. Previous to 1.11 we could set an object to be 'Temp on rez' and leave it out on our parcel indefinitely, because it hadn't technically been rezzed.
But I'm sure you've learnt how to deal with screaming residents now. So you'll be fine...

Peace!