I noticed this happened earlier today, first time witnessing it beyond the 1st round of course. There was absolutely no kills for 60 seconds, so I think perhaps it falls under the old MOTF rule where if no one dies for 30-60 seconds (forget what the actual value is) MOTF pops. If so, that's nice. It was pitch-black fog and we couldn't find the other team, all of a sudden MOTF pops and boom! You have an objective.
1st round MOTF wouldn't be so bad if it was guaranteed to always have a centralized location--but that's a lot to ask of the scene editors to guarantee that. You'll always have people say "Ughh! Red Team is 2 seconds faster to flag than Blue Team!"