Politeness is simple & always returned.
Anyone running up on us, or me if I'm solo out shooting, is going to be cause for pause. Be they a 300lb "scary" looking dude all colored up, an 85lb wet noodle, or an 85 year old gramma.
I'd say start with hey my names xxx, I'm member xxx over on NWF, how are ya?...
I ain't just gonna run up on ya dude. That's a figure of speech....Most people weird out when some tatted up dude approaches them. I'm used to that....chances are I'll be covered. I'm just a random azz dude, cool AF. I'll probably start by explaining this place etc......just like you said......then everything's good!