All I can say is I have had a plastic drop-in bed liner in my truck since the mid 1990's and can't point to a single issue that has been caused by it. I will admit that the camper shifts more than it probably would without it, but once it is snugged against the front wall of the bed, it stays put.
I also use Totklift tie-downs.
-2000 Chevy K3500 CC DRW 7.4L, Auto; 2000 Arctic Fox 1150 WB; 1999 Bayliner Capri 1800LS Outboard
-Air Lift bags, Torklift tie-downs, Superhitch w/48", Rancho RS9000X, K&N FIPK, MagnaFlow exhaust.