A few times during this past Splatfest, my team and I practically locked the enemy team inside their spawn. One match on Blackbelly, we spawncamped them from about the 2:00 mark to the end of the match, and they only had 5.7% when the match ended (we had 85%. And won.). And a couple of times on Triggerfish, I kept any enemy I saw from leaving the spawn area for at least one minute (in one case I remember with the Octobrush, it was all three, and I got a triple-kill from behind to start it off. And never died. Which felt awesome when I saw that in the results, I hadn't noticed during the match.). And I spawncamped on Moray Towers for about a minute once with a teammate, which felt awesome and rewarding after fighting our way to the spawn point (and we won that one, if I'm remembering right).
Also, for some reason, after a certain point in both of the Splatfests I've played in, I switch weapons (to the N-Zap '89 during the second one, and to the Splattershot Jr. during this last one) and go on a hot streak for most of the rest of the day. It's weird, mostly because that never happens outside of Splatfest but also because I can't explain it at all, I just sort of go from losing to curbstomping to winning close matches, in that order, both times. And yeah, I'm sure part of that was getting good teammates, but that can't be all there is to it.