If there's a sign I'll take it off as it's clearly their policy. It's their shop and they have the right to serve who they like just as we have the right to shop where we like.
If someone TELLS me to take it off they can't get stuffed.
I've flatly refused before and just out stared the person on the till.
I'm the same with that rubbish about not using a mobile phone on a forecourt.
"It might cause a spark?!"
How the hell do they think the internal combustion engine works?