One hotel I went to, the front door was open but the front desk clerk told me he had to see my ID and I had to sign in. I said I left my wallet in my car and I would go get it, but immediately left the area. The provider was livid.... at the hotel, not me when I called her and told her.  

Another better provider left her room key in the gas cap door of her car so I slid right into the hotel like I owned the place. I thought that was a great idea.  

I'm sure there is a lot more smart ways we can work around this tho