As a new player, less than a week old, I would actually appreciate it if more expirienced players would coach, give pointers. How do you expect newbies to get the most out of thier toons if noone to guide them. How will you know that person going to that 50 HC didn't gimp along to get there, or omg it's their first time and don't know the layout or all the ins and outs.
Some people do. When I'm leveling up an Alt I always ask at beginning "Does everyone know the FP?" If someone says no then I will explain it to them as I go. I figure a few minutes of investment now may lower my aggravation level in the future if I group with the person.
If the person is friendly and engaging I'll happily help them out. I've been known to run random friendlies through lower level FPs multiple times with one of my 50s to help gear them out etc.
So general rule of thumb. Be honest that you don't know the FP. Be friendly and it could pay off for you in a big way.