I shifted one of them today, to find to my complete surprise it was rather easy, for me to go out there with a pot of J&J baby shampoo,paint brush and razor blade. Mind my offending sticker had only been there about three weeks and I guess the lack of sun combined with tinted windows prevented the sticker glue from curing.
But if I were confronted with a sticker that traversed heater element tracks, not only would I think poorly of the dealer I'd with a scalpel gently cut the sticker close to the heater element to remove the bulk of the sticker before hooking up the corners of whats left to feed liquid soap into those corners whilst GENTLY peeling.