I've heard the "too much tape on flat rate" crap at my PO before. I could understand if it is brown tape, but I use clear and everything is still readable.
If the gorillas and monkeys they hire, did their job and quit bitching about it, everyone's packages would arrive safe and sound, not to mention faster. As for the machines, I don't think at anytime a Priority mail item should even contact those machines. you pay a little higher rate for Priority mail, they should really give it priority!!