The idiosyncratic desire of an owner of an expensive yacht or motorboat who deems a certain, although often trivial, point to be very important.
A 'red exhaust situation' means that it matters to the owner even if you might think it pointless or ridiculous.
The Riva Aquarama, the most iconic speedboat ever made has red painted exhaust outlets but the paint gets easily blown off due to the chromed surface. The owner of a Riva Aquarama will often insist that the exhausts are red. Hence a 'red exhaust situation'