I was looking around for tourneys that might be a nice trip to and was reading Laurels rules and they forbid any owner or trainer who has an interest in a race from playing it.
From playing that one race. It doesn't say what happens if they have a horse in a race that's a mandatory race. Of course, these rules don't say anything about mandatory races, either, just a pool of races from eligible tracks.
Laurel is not a "nice trip", by the way. A very ordinary, somewhat run down facility, in a very ordinary suburb.
Colonial Downs would be a nice trip if you are looking at that part of the country.