They can not legally stop you or check your receipt unless they have evidence you stole something.ni don't even show them my receipt. I will often times leave the receipt right there because I have that right too, but I will never wait in line twice especially once I've payed and officially own it.

Once you pay for it you don't have to have a receipt even. It's yours whether you accept the receipt of not and since it is your private property they have no right to your private property or to detain you any longer.

I already looked into it. They can not stop you or make you do any of that. It's all voluntary.