I use the Roemer release also. When a fish hits the "cheater" line, does it release the Roemer release? As I am sure you know, you can really "load" your rigger rod with this release and when you want to manually release your line, you need to give it quite a tug. For this reason I would not think that a fish hitting the "cheater" line would trigger a release?
even a 10 inch salmon on the roemer releases, i have them set pretty light and like you said you can really crank down on the reel, but i have had no problems with this set up. one thing ive found with the release if you want it off the ball, is that you can release several yards of line off the reel, let the drag take it back, and you can get the roemer to release without reeling up the ball (this may have something to do with the drag on the 20 pound test as most dont go that heavy with the main line).