If someone carelessly allowed plastic clothing tags to be washed along with clothing and put in a dryer, would the heat do anything to the plastic?
it can. I put the bottom half of a hunting suit in the dryer, and the plastic buckles for the shoulder straps came out brittle and broke the first time I went to use them.
Normally, those nylon (?) pieces with a tee at one end, and ~1/4" flat piece on the other will go through OK. Other stuff can easily melt onto the dryer drum. Saw enough of THAT in the bad old days.
My wife tells me that it does no good to knicker elastic either.