Well I'm a Civil Engineer and have worked on large scale construction projects where you do get a lot of foreign workers, mainly polish and now a lot of Indian and I remember going into the canteen and there were posters up on the walls saying "British Jobs for British workers". I can imagine a few of the polish and indians would have felt it was directed at them. Their situation is no different from ours though.. Just going to another country to try make a better life for their family and self's.
But true, as far as stickers on cars go. I have yet to see that in the UK. Not that I condone vandalism but they are going about things the right way if they want a sharp key scraped along the side of their cars )
David