Jeff Burton Drives for Cingular but if he wants to drive Nextel Cup, he runs a Nextel Decal, and has a Nextel Patch on his firesuit. If Rusty Wallace or Sterling Marlin wanted money for putting thier car on the pole, they had Budweiser decals on the fenders. It is just how contingency sponsors work.
Lets say for instance that You have a truck sponsored by an exhaust company other than Flowmaster, An electroncis company other than Dr P., etc : I would think that your primary sponsor would not have a problem with you working with another company (running a small sticker and a part that nobody will see anyway) if you had a legitamete shot at a record.(and tons of exposure) It is pretty simple in my mind.
JRich made pretty much the same point. Lets say for instance that Larry Dixon Wins the Bud Shootout in the Miller Lite car. Sure he had to slap a sticker on the car and wear a red hat for a photo op, But I can tell you the Miller execs have a ball when they take Bud's Money. As a matter of fact, as a sponsor, I might sink more $$ into a program out of spite.