I also upgraded at 9L pre-merger ('08). I'm fully expecting to be downgraded before this year is over, and when I do I guarantee you I will NOT be wearing 4 stripes in the right seat. That, in my opinion, is HIGHLY disrespectful to the guy sitting next to you. Note - This does NOT pertain to check airman and their jobs.
The dice were rolled and it is what it is. I've enjoyed being a CA and learned an awful lot. But when it comes time to go back to the right seat I will respectfully put back on the 3 stripe eppaulets. At least I'll still have a job which is more than I can say for a lot of pilots we work with.