Because those are the rules.... to stop riders taking the mic by picking and choosing their meetings and denying suporters not seeing them. And having to use R/R. By doing this its a deterrent to the "dodgy burger" that has happened in the past. Yes in this case it means the public wont see the rider in 2 other matches but as a guest is now allowed for the top 3 the fans won't be short changed and will see 7 riders line up.