In my opinion a better solution would be to increase the delay for flags to unlock (a few maps like Omaha already have this, although it's still a fairly short delay)
I like this feature on Omaha, it gives the defender a chance to get back. Tbh the
real solution would be to make Sector Push maps behave like they do in more recent games. For example, in Operations in BF1 or in Territories in RS2 (both are basically sector push), each team gets protected spawn points that the other team can't venture into.
You see in this map, that the flags in play are in a combat zone and the team spawns are in a protected zone at the next or previous flags. RS2 does the same thing. In BF1 I think you even get the added delay before the next set of points open. There's a scripted 'mortar barrage' that you have to wait for before the next sector opens. This allows the defending team to prepare and keeps the attacking team from pre-capping.
Another nice thing it does is give the attacking team tickets when they capture a sector. i.e. you get 100 tickets as the attackers, and if you can't cap that sector before tickets run out, it's game over. what this does is stop the game from dragging (like when Russians can't cap the first sector on Seelow). So instead of waiting the
whole round for 1000 tickets to run dry, you only have to wait till 100 tickets run out (or a lockdown timer kicks in like RS2) and we can move onto the next map.
This would be the ideal way to do sector push imo. But in BF2 it's either; not possible, or the coding to do it is so convoluted that it's a real pain-in-the-ass to implement.