Just because a suite is available for booking online does not mean it is available for check in at that particular moment. It might still be occupied, it might still be dirty, it might be a crime scene (see door kicked in don the hall thread).

In all these instances and more, that suite would not be available for upgrade.

This is why, every time I hear somebody whining about a suite being "available" online when they don't get a suite upgrade, I just shake my head.

Cheers,