Can I sleep in my car here?

I wouldnt do that

Most businesses will tell you that their insurance considers such a liability. They cannot willingly or directly give you permission to sleep in your vehicle on their property. You will be considered an intruder or trespasser who is not covered or has rights like customers.

Yes, I had no problem and the lot was patrolled by a security service.

Never tried it.

Why would you want to do that

I would not do that.

You need to ask store manager