Sap flags now?

While waiting outside Kara for other people to show up, I notice a few flagged horde also hanging out. I go about my normal routine, pick my favorite on out, stealth and go sap him. Bam, my pvp flag pops up and I'm a flagged ally in the midst of 8-9 horde. Stay stealthed, sprint away, hide by ogres for 5 min.

Now luckily I made it out but is it now safe to assume I can no longer sap flaggd horde while remaining unflagged myself? I kind of see why they would do this, it just would have been nice in the patch notes.

Guess I'll just have to remember the old days of stopping summoning stone summons, stopping people mounting up and generally being a PITA .