I appreciate the suggestions and input.

When I got to IAH last night, my bag was not on the baggage claim carousel. I checked with CO Baggage Service, and they found my bag. It had come in on the earlier flight for which I was refused stand-by. So, my bag was at IAH while I was still in SEA.

Thanks for all the input! Hopefully, this will be a learning experience for a gate agent at SEA.