Ed French mentioned in an interview that domestically only about 10% of elites get upgraded to suites. It does happen (as people have noted on this thread), but that doesn't make it the norm. And if one asks for it (as USIrritated does every time according to his posts), sometimes there's a better chance than just hoping. But a lot of things go into play - length of stay, occupancy rate, how many other elites also checking in & requesting a suite upgrade before another elite, etc, etc.

Cheers.