I've been playing 2/4 NL and won 700 and 1,100 within 40 minutes both times. In a live homegame it pisses guys off when you just get up and go but is it the same online?
Online? Hell yes take the money and run. As has been said, you'll likely never play with these people again.
Live is a little trickier, both the homegames you mention and at
casinos. Where I play if you get that reputation among the regulars you'll find that over time you won't get much action when you have a hand.
I would just hang around for a while and play uber tight. Who knows, your heater might continue. A lot of pros advocate staying put when you are on a roll, They say if you leave you'll never know how much more money you could have won. I'm hardly a pro so I prefer a more subtle hit-skip approach. I look at my profit and set a definite stop-loss amount.
I only do this if I know I'm going to being playing these same people week after week. For example, to use your numbers, if I was up 700 I might play for a while longer and leave when I got down to 675 or so. If anyone grumbles I just make light of it by saying I've donated plenty of money to everyone else's cause so I'm going to be smart for once and get out of Dodge now while I'm ahead. Humor usually helps to diffuse anger.
One time I did this a guy who had been really pissed came up to me later and (sort of) apologized. He said he wished he had that kind of discipline.