I was thinking IR from the sun rather than somebody else.

Or here's a thought. Maybe I've brought this up before, so forgive me if I've already said this and been shot down...

Does the player wake up when it gets "just any old IR command"? Or does it only wake up when it gets valid IR commands from the Rio remote or (if enabled) the Kenwood remote?

Because if the former, then it could easily have been any number of IR leakages in the parking lot, including the sun.

Corrolary follow up to that question:

Even if the default kernel only wakes up in response to a valid Rio/Kenwood IR command, what about Hijack? Since Hijack has the IR translation features, and hence, just any old IR command could theoretically be valid for Hijack, does Hijack wake up on just any old IR command?