[SPOILERS]Dolores kills a human outright by aiming at their head mid-season. Then it isn't mentioned again.[/SPOILERS]
I always assumed something in the suit lining made the guns faux-fire, and the suit responded by exploding a pocket of air or something. But then you can see The Guy In The Black Suit (I've forgotten his name) load his revolver by manually inserting bullets, so I have no idea how that'd work. It's probably one of the only things that bothered me about the series.
It doesn't especially bother me though. We know that TV and movies generally have a convention that trauma that would put someone in the ICU in the real world is brushed off as a flesh wound. And I'll accept technobabble about the bullets. I'm also happy to accept that maybe Westworld takes place in a culture where theme park risks on par with base jumping are considered fine and proper.
http://www.cnbc.com/2016/12/27/what-it-would-actually-cost-t...
Edit: popular holiday destinations like Mexico are reasonably dangerous, maybe Westworld is on the other side of the border ;)
Especially since a lot of hosts "work" at night. :)
Yes, the hosts are busy, but it's definitely possible they could be recalled to a location for pickup (or whatever) when they're free.
Something else you pretty much just have to accept is that through all sorts of mayhem, the humans stay safe (well, until the end at least). There's some rather inconsistent hand waves around guns and bullets but one has to believe there are still ample opportunities for serious injury in some of the scenes we see.