If my buds shoot a good arrow you bet I fixate on that arrow's nock!
It can be a great focus aid and make for equally good shooting (sometimes really good as I've blasted nocks off on the 3D range). With today's carbons that means there's a good chance of the recipient arrow being ruined.
Standard practice then is to buy the victim a coke at the halfway house or at lunch break. Yeah it's not much considering the cost of an arrow, but then maybe your buds shouldn't shoot so good and tempt you ;-)