If we disable the SL spawn in flag radius we'll only have squad leaders hiding in a bush while the rest of the squad is capping.
if it is far enough that hiding is not quite worthwhile (should not be too far, you get it), then no people would hide. Again, the whole benefit of SL spawn is more like regrouping people (and enjoy gaming with friends), not to let people spawn in the middle of a knifefight. 4x seemed to be too close (as some flags are massive towns, like Cagny) - I think a ratio of 2:3 would be good and not too annoying.
Or we could scale it with another thing, such that the distance would at least allow a SL to run+walk for 20 seconds, which is the necessary spawntime for regrouping, it is more scientific as well.
And it makes a whole world of difference of, even the SL hiding in a bush, as you now could expect the reinforcements to come OUTSIDE of your flag instead of constantly popping up in your flag. A lot of lame SL tactics could be prevented this way, like a stubborn squad refusing to leave a church tower in antoville - since as you cap their flag, they couldn't anymore respawn and you could really "clear" it with brute force.
This would further cut down lonewolfing as well. And we don't need to embrace the evil ideas of PR... :p
So, if this is possible, first test it, then if it's good, devise a good UI for it, we have push mode circles, I bet this is less difficult than the other tough things of the engine.