I'm kinda new to float fishing (or even drift fishing) and any kind of 'combat' fishing in general. So this may be normal and I probably should have kept my mouth shut - but I still didn't like it...

Last January on the Snoqualmie, (on a week day morning) a buddy and I had a stretch on the upper Snoqualmie to ourselves. We were float fishing with jigs and fighting the ice in our guides with numb fingers. A guy shows up (we fondly refer to him now as 'grizzly adams' based on his looks and attitude - big, hairy, and pissy) and claims his spot on a big rock about 20 feet downstream from me. Keep in mind that there was plenty of room for us all to have 100 or more feet to ourselves, but he wanted the 'best' spot...
So I let my float drift down to him, and not wanting to be rude, I cut my drift short and just aimed farther upstream. After about his second cast with his huge softball sized cork float zinging across the entire river and way upstream past my buddy and I, he eventually crossed my line well in front of me. Our lines did not snag, but came real close. So being a little annoyed that he crowded me in the first place, I politely asked him if he happened to notice that he crossed my line. Oops! He came un-glued, cussed me out, threatened to kick my a$$ and informed me that he has been fishing since I was just a little kid no higher than his knees and how dare I question whether or not he knows what the [Bleeeeep!] he's doing... (it's time like this that I've considered renewing my concealed weapons permit...)

So, how does this work? Should I expect someone to intentionally cross my line and fish the same drift I'm on even though there is plenty of room? When fishing with other float fisherman, is it OK for me to cast upstream past them and let my float drift down past the guys lower down? What about when fishing with other types (drift, gear, etc). I know every river is a little different, so I'm just looking for some ideas. If you happen to know the 'rules' for the Sky, Snoqualmie, or Green, I'd be interested in hearing those in particular. Thanks!