1) I have no knowledge of pvp itemization (or pvp in general), but it sounds like you haven't done anything wrong. MS>OS, which also includes pvp in the latter category. I mean, I can't imagine a pvp spec contributing to a raid and only collecting all pvp-relevant gear pieces...Like, what? I can't understand how that warlock would become upset about that.
2) So, don't expect to be banned. However, for the sake of discussion, I would like to clarify something. Even if you had broken the rules, the report needed to have full proof of your wrong doing:
http://forum.warmane.com/showthread....=1#post2651922
And the first violation would have granted you a 60-day ban. It doesn't matter how many people file that report, the duration wouldn't change. In fact, if an entire guild submits tickets, they'd do more bad than good in that case. They would just create extra work for the GMs, because they would most likely not have any proof to support their accusations.
[edit] I just googled that trinket. I remember how my former Icecrown Guild Leader said something about this being used in PVP. However, I still don't think that you did the wrong thing.
PVE > PVP unless explicitly stated at the start of the raid.