If someone smacked me, I don't give a fuck whoever else is standing there - the cvnts gonna get a smack back....
That said, it's that exact attitude that has gotten me a proper kicking before now

Me on my own, and the other guy with about 6 mates

I had no fooking chance
Still, it's the principal. You smack me? Then expect one back, hopefully hard enough to put you down, so I can do a runner