I could send in a report claiming someone has red hair and it offends me, it means nothing, the only time you can get reported for PK is if you're abusing lag and hitting the flag unkillable, lagged out (not bannable) unless unkillable multiple times pking and continuing after being dc'ed, or boosting (at spawns in towers etc)

Also regardless if the person reports it's staffs job to verify it is actually happening.