I just arrive in SF last night - staying at a Sheraton. I am Starwood platinum, and know I am "entitled" to a suite upgrade if available.

Upon checkin, I asked "are there any suites available" and was told no, they are all sold out.

I then politely asked - is it possible one might be available later in the week. He said he would check. I said it wasn't a big deal, I could check back in a couple days.

He continued checking his computer, and voila - assigned me a nice suite for the entire week.

I don't know what would have happened if I had demanded a suite - but even if I'd have gotten one, it would have left a bad taste all around. Instead, I did what our mom's always told us "asked nicely" - and I end up a happy customer.