Yes team killing makes you lose experience. A big chunk of it too. I average 250 attack
in monty and get about 70 to 80k exp. I had a 290k attack game and a noob crossed
me so i tkd him and ended up only getting about 20k exp. So its a considerably large
loss

u get next to 0 xp if u sink an allies ship and if u just attack them, it decreases certain
amount of xp, but its noticeable amount

It's easy to get negative xp if you are in a normal room and don't get any attack before
getting sunk.

You don't even have to hit anyone.

Once (one year later) i got negative xp! I dont remember how, maybe one of my proxy torps
sunk an allied DD, and the team attack was nearly 0 when i left the battlefield. The
strange in this picture that the higher lvl sailors got higher negative xp. :)

Driving over my guns while i am shooting at enemy BB's should be bannable too, so should
spamming, deal with those first than worry about tkers.

please do not teamkill. teamkilling is a bannable offence

Oh.....thanks for answering that....fyi, i dont tk but other people occasionally teamkill
me with torps or guns

this shouldnt even be an issue. shoot the opposing team, not your own. >:/

It gives a big penalty to experience.
in Shared exp rooms u wont get final negative experience, but will stay in a positive
number which can be from 300 to 9k or more , it depends how much attack u did, and
how much damage u did to ur team mates.
In normal exp rooms, u will get even final negative experience. but it depends also on
attack and how much tk u did.

I believe the answer is no. However in an battle should you attack your teammates
it decreases or wipes out the experience you will get that battle.