In a theoretical Open PvE mode: killing another cmdr.
I'm sure the defense would be "oh I didn't mean to / I boosted accidently / they were on the wrong side of the toast rack" etc. But the second time it happens? the third? FDev get to go "ok soft ban for you, until you git gud at flying". If it's a proper PvE player, they get a time out (and remember they don't want PvP in an Open PvE Mode), but an actual griefer gets booted out.
Given enough repeat offenses and the bans get longer.
Of course a "proper PvPer", who wants to fight combat equipped cmdrs, shouldn't have a problem with any of this either.
I thought this wasn't rocket science to think through.
EDIT: sorry @Filthymick420 I've made edits after your like, in case you want to remove it
But it is not the the "proper PvPer" that is the cause of this, trying to make it that way is simply dishonest.... and it is not these players who the PvE players are worried about, it is the other group of PvP players that deals with ganking and other activities that are more for the lulz etc, to have the other player to react to them being "mean"