Yeah, I thought about it. But I think most players would still whine, so i'm probably going to put the flag on the ground somewhere and change the interior a bit.
I'm not sure if after this I'm going to continue making maps, though, I don't really see the sense in making a siege map that can be conquered by random attacks. But that's exactly what most people expect. Siege is for them just another form of team deathmatch, where, instead of simply having to kill the enemy team, you also have to walk towards a certain spot on the map. It seems the multiplier is more important for most people than the fun of conquering a challenging castle.
Maybe this would be different without the multiplier, but I'm not sure.