Griefing: In online gaming, someone who purposely seeks to annoy the other players, especially his own teammates.
Next round no real issue game continued as normal
Third round, Objective A1 and B1 were lost in 30 seconds from spawn, however this time I saw why, a team member placed their full load of C4 and puled the trigger. In short Griefers are now invading BF:BC2.
This more then anything is to serve as a heads up so that if any of your Objectives magically go 'boom' you will know what to look for.