When Cyberbird says: I might even consider now, taking my old - left hands seat - job on a 737 in europe up again ...
I don't consider that the same as a DEC.
I'm in a same situation. When I left my previous company a few years ago, I was in a let seat after some years as a F/O, climbing up the seniority system. After my resignation, the people running the show told me that they were more than happy with my work for the company, and if I ever for any reason felt I wanted to come back, I could take up my old position as a Captain.
Although it is a 'grey area', this old company knows me as good as I know them, I've been working for them for several years, did a training as F/O and did my upgrade with them. Also, there wouldn't be many F/O's with my experience flying for that company... Therefore, I don't think going back to a previous employer where you did serve a certain amount of time before can be regarded the same as a DEC case.
MR8