Jeepers creepers, I can see this going very bad, very quickly. If I was him, I would be incredibly put off if someone knew me but kept it to themselves. I think it's important to consider how it could affect him if you follow through without giving him a heads up in advance. It would seem pretty suspicious of you, and I can't imagine that would add anything positive to your experience. If the shoe was on the other foot, would you be okay with him doing the same to you? Just something to think about...