I can't comment on Astral's (OP) exact situation re the sandwich on the griller there. But it might not be as cut and dried as you think.
When I was at college in the 70's, we would go down the pub at lunchtime and get a toasted sandwich along with our drink. When the toasted sandwich was brought to us, .. wait for it ... it was always still in the plastic bag that it had been grilled in.
Seriously! And I can't say what the plastic felt like before it was put under the griller, but by the time the cooked sandwich was handed to us, the plastic was quite brittle but could still be pulled off in one piece easily enough.
I could be that the student in question had previously been served this type of sandwich, either in the UK or elsewhere in Oz - who knows.
Just my 2c - but I am still appauled by the sheer ridiculousnes (is that a word?) of the nanny state we live in these days generally
