Whatever you've participated in on normal realms is completely irrelevant, and being able to duel assassins is also irrelevant. As you're aware(?), games can hold up to 64 players, and these FFA events take a minimum of 9 rounds. The majority of players who participate—especially the ones in other time zones—usually end up leaving early because they don't have the time to watch a bunch of assassins duel each other for 10 years.
I imagine the point of banning light traps from FFA is to make things a little more interesting, because watching 5+ assassins attack each other with their eyes is suicide inducing.