As someone in the UK, if I want to play with someone in the states, even if we're in open at the same time, and in voice chat, I have a hard enough time instancing with them even if I want to.
If we were opposing sides of a BGS conflict, we could continuously fly in open for weeks at the same time and never see each other. Even in the same system, unless both players happen to be in supercruise at the same time, it's pretty rare to meet each other - if someone's in a USS, or a PoI like a station or a CZ or a res site, someone in supercruise cannot perceive them, nor they the person in supercruise. Outside of heavily trafficked systems like engineer bases, CGs and Shinrarta, the only time I ever seem to see people is at the stations. Even at engineers I've seen more players landed on pads than I've seen in supercruise.
Even if I do manage to catch someone, interdict them even, that takes me out of supercruise where I can no longer detect the presence of anyone else in the system - and for the cost of, what? Slowing them down to the tune of however long it takes for them to high-wake and come back, so all of a minute and a half? If they're doing something like cop-killing they're not going to be running some squishy trader build that can be splatted in under fifteen seconds, and they only have to get by you once to summon more cops to kill.
Conflict zones? For effective bond turn-ins for the BGS, you need to be doing shuttle runs. You want to stay in the CZ and defend it from any players that drop into it? Not only are you making yourself less effective at helping your own efforts, they can just go to a different CZ - and this is all assuming perfect instancing. So please explain, given those circumstances, how I or anyone else is supposed to enact any kind of effective PvP blockade upon a system's BGS?
In order to have any kind of constructive discussion on how to make the BGS balanced in terms of defending groups, attacking groups, random actors, and wandering murderhobos, we need to accept that regardless of mode it's not possible in this game to blockade a system, and design the balance around this. Hopefully, the issues we've been talking about on these forums and elsewhere are something that will be addressed in 3.3.