You'll always get incompetent people who are unwilling/unaware and not give you ammo/health though. I think the point they're trying to make is that they would rather implement an alternative instead of just doing that. You could implement that system and try to balance it out, but at the end of the day it doesn't promote teamwork in any meaningful way. If anything it potentially discourages it, because you're not communicating nor coordinating with those players. Not to mention it can give players the impression that they never need to bring out their bags because their teammates are just gonna take it from them via that system anyway.
Plus, if you are with a good squad, you should never come across that kind of problem. Even then, you can try to find a different Support player if the one you're chasing is clearly not going to give out ammo.
That's depending wayyy too much on there being more than one support. There's been rounds where people literally have to beg for people to throw out their kit items/health and ammo. It's
stupid to say it discourages teamwork.
If you really want to make people throw out their kit items while implementing the steal system:
-10 HP per "steal" while alerting the team in team chat "NEED MEDIC" this would make the medicbag faster to heal than smashing Q 9-10 times for 100 health
-One magazine reloaded/no explosives gained via steal. "NEED AMMO" is alerted to Team. This would make the ammobox beneficial in throwing out in reloading (nerfed, ugh) grenades and XM25/M320/C4's AND faster than smashing Q to get one magazine at a time to your max for your pistol and primary.
BOOM. SOLVED.
Not doing it isn't solving the teamwork issue. The teamwork issue "people are going to be dick anyway and not work as a team" is always going to be there. In fact, IMO, the "teamwork initiative" is mostly a fools errand. You're not going to change the player base unless you throw big huge "SOMEONE NEEDS AMMO/HEALTH YOU DUMBFUCK" at people in text in the middle of their view every 10 seconds when someone requests it. So you might as well let people "steal" even if it "discourages team play" because it
helps teamplay by getting shit off the "selfish players."
I mean if blinking icons on the minimap can't get people to notice that someone needs health and ammo, nor is running RIGHT INTO THEIR FUCKING FACES WHILE SPAMMING Q TO HAVE A BLINKING ICON IN THEIR VIEW in 3D space,
nothing but allowing stealing is gonna help.