Only ammuntion for guns are variable even in H2H.
If someone is dropping abnormal amounts of bombs or rockets, then (provided you've either caught it in a film or a screenshot to prove it) it can be considered a cheat.
As a matter of fact, a similar incident happened quite long time ago, where someone was seen dropping abnormal amounts of bombs - which HT reacted quickly to.
..
However, Snubby, like others have mentioned, cheats or hack problems are to be dealt with directly to HTC staff, and not to be mentioned on boards. This thread will probably be locked off when Skuzzy sees it.
Send an E-mail to HTC. Try to include your film or screenshot of the event, and perhaps the roomname, the name of the alleged cheater, and time and date of the event. I'm sure HTC has some sort of internal logging system which records what is going on where - they'll review it, and if someone's caught doing something bad, he's gonna be banned from HTC servers.