Like is it generally frowned upon if you get too close to enemy spawn because it is spawn camping?
Should you call hits if your own team shot you?
Does ricochet count as hits?
How do you execute a knife kill, and does it only count if the enemy hasn't noticed you and if you do it , or can you engage a enemy around a corner and try to land a stab as they try to shoot you or is this not allowed?
Yes, spawn camping is bad and you shouldn't do it. However, I've done it myself on a few very limited occasions. I will typically only do it if I'm on a team that is getting rolled super super hard, since I can usually sneak around the bulk of the enemy team, and even then only for a time as people will get annoyed by it. In general, spawn camping is bad though and shouldn't be done.
Yes, you should call your hits if your own team hits you. Friendly fire still counts, no matter the situation.
Ricochets depend on the site. I generally don't like it, since I think it can promote bad gameplay in my opinion, however I will take ricochets if the site's rules say that ricochets count, like at Gunman Namsoft events.
For me, knife kills depend on the event. I think for most games, they should be a stealth kill. A gentle tap on the shoulder and a "knife kill" whisper, with the person not then yelling out "hit", instead just walking off quietly. Because stealth kill. I prefer it this way as it stops over-energetic airsofters from running around the site potentially smacking some poor kiddie in the face yelling "melee kill". However, at some events I think it's fine to have melee kills that aren't stealth kills, as long as it's said beforehand. We've done a few private games with the Worthing lot at the UCAP bunker in Portsmouth where melee kills are allowed and it's a good laugh, but it has to be with a LARP safe weapon. Although, I have never used my jiujitsu for melee kills in airsoft and I think it would be frowned upon if I disarmed and threw an airsofter on the ground ?
And about the other question that seems to have popped up about hit takers, I give them three strikes and they're out. Sometimes they just aren't hit and I think a lot of airsofters overestimate their guns. I've had people yelling "take your hits!" at me, while I'm watching their BBs land 10m in front of me, or they're shooting the wrong part of the bush I'm hiding under because they haven't actually seen me yet but think they have. However, if I hit someone, see it hit them (magnified scopes are great for this) and they don't take it, I'll give them another shot to the torso. If they don't take that one, I give them a Kicking Mustang special in the face. It generally doesn't come down to that as most people take the 2nd hit. Sometimes they just aren't sure it's a hit. Sometimes they think nobody can see them when they get hit, but are convinced when they get hit a 2nd time.
Also, trades happen. I don't think there should be any "yeah, but I hit you first" argument when we're talking about milliseconds. Obviously if the person hit first was hit way before hand, didn't take the hit and then shot back then sure, that's not a trade, but when two people see each other, shoot each other and get hit within milliseconds of each other, both players should call it and walk back to respawn or call for a medic, depending on site rules.