[Boris the Blade]

I double tap people now, and haven't had a problem with people not calling hits. However, with that being said, I've also had the rare few who don't call their hits. Follow these easy steps, and you'll resolve the problem.
1. Make sure your gun works! Yes it sounds elementary but guns do jam. Check that your gun works properly before accusing someone of cheating. Give the person the benefit of the doubt.
2. What range are you hitting people at? Getting hit past the effective range of an AEG or pistol is naught but a tap on the shoulder, people with lots of kit, or baggy kit wont feel (or hear) these hits.
3. Shoot people until you see them call hit. Many times I see people take one shot, miss, and then have their target spin around and shoot them. If you have the drop on someone, shoot once, wait a second, then shoot again until a hit is called.
4. Try to remember what the person looks like. The next round you play, try to get the drop on them and shoot them in a way that is undisputable. I like to use a training knife, and make contact (gently).
5. Parley (Parlez). Talk to the person off the field after the game, or talk to a host regarding the situation. At FR we had a good system, if you think you hit someone, and they don't call the hit, call yourself out, walk over to them and discuss the situation while on the field.
6. If you and your opponent shoot each other at the same time, call your hit, then tell them to call their hit, you are both out. If you shot at each other at the same time and you did not feel a hit, call it a hit anyway. This avoids problems in the future.
7. If all fails, hose them down, and ignore your hits until they call theirs. Not my preference but if the other 6 steps fail this one is sure to work.