I have said it but I try to ask like this....
"Would you mind if i borrow that?"
You know it is more direct, and it doesnt make it sound like you have no other options. I am one of those type of people who respect respect know what I mean?sure there are times I am rude but it is rare, anyways back on topic...... When someone said "you HAVE to..." it makes me feel like I am being forced into something. so I tend to do the opposite of what they say.

I am a rebel.