The sentry and laser, and other entities don't act like they used to. Well, to better phrase it, they don't operate the same way they used to... now instead of constantly scanning for an enemy, there's a "trigger" that's spawned, where enemies can be picked and chosen.
This translates as people not being able to "skip" through lasers, for one thing. I mean it's still possible, but hardly. They'll still get hurt maybe a few frames after they thought they made it through. (No, it's not unlagged)
Also, this means the sentry can target a flag carrier, an enemy going towards the flag quickly, an enemy close to a flag, and just a regular enemy and consider which one to hit first. I did it pretty much in that order, it's just a few case switches. It's not consuming a lot of horsepower or anything.
The same with the turret grenades.