Yeah, but I thought it's not that important, there are more important suggestions here at the moment (I found a way to do almost the same without additional functions). Entities must not be multiplied beyond necessityThat wouldn't be hard as it's mostly the same logic as the existing building prereqs. I really wish I had Lua for this sort of thing. However, I don't see why using upgrades for this wouldn't work as AA mentioned. You'd have an expensive unit that upgrades to a cheap alternative that requires a building and has the same stats. Having the upgrade available would remove the expensive unit as a build option, like how connecting iron for swordsmen annoyingly makes warriors unbuildable. Even with building anti-prereqs, you'd want the cheap & expensive variations to be on the same upgrade chain anyway, no?

Let me summarise my requests and the results of our discussion over the last month (just in case they don't get lost in the forum history and because I asked for a lot of things, but not all suggestions were important and necessary):
1) Correction of the "disallow trespassing":
a) Helicopter or any other air transport should not be able to airdrop across the border (as well as paratroopers)
b) All visible units that somehow entered in foreign territory should be bouncing out in case of peace and the absence of the right of passage agreement (either at the start of the turn right after changing borders or right after player completes his turn but before other players take their turns). Bouncing should not extend to invisible units, cause they must have an opportunity to attack even if they were revealed.
c) To tie the "disallow trespassing" to a government type.
d) (Prohibition of the air recon on foreign territory in case of peace and the absence of the right of passage agreement is not necessary).
2) Auto-recon function (activated at the start of the turn).
3) Allowing rebase missions to be intercepted.
4) To restrict units to loading once per turn.
5) To prohibit the construction of some improvements or wonders for specific governments.
A List "if time and desire will be":
1) To make precision bombing truly precise so that if you know what buildings are in the city, a window opens with a choice of a specific target (just like with a stealth attack against units) or at least, prioritizing buildings for precision bombing targets by flags (for example: first "both flags", then Mil-flag, then Ind-flag and then others).
2) To allow loading transport helicopters onto the carrier.
