I agree with you and do the same thing. There is a lot to be said for the personal touch and being able to chat with the person doing the actual check- in. call me Old School, but you become more than a reservation number when you deal with someone face to face. I think that you stand a better chance when you are right there in front of someone than trying after the fact.
Once they know that you already have a room, I would think it easier for them to say it's not possible and have to relocate you. I would rather know BEFORE I get to a room and settle in, then have to wait for the beelman to come and relocate all of my gear. I want to to head out and start enjoying my stay at that point.
just me.