Originally Posted by
sethb
The SPG wording says they'll upgrade to a suite if one is available.
A common misconception, which causes great consternation when people don't get what they mistakenly believe they deserve. The actual commitment is
An upgrade to best available room at check-in — including a Standard Suite
Not all suites are Standard Suites, so just because there's a suite doesn't mean a Platinum is entitled to it.