In the end it all depends on the rules of the server, and very rarely does a server state "do whatever you want." Even if the server has no specific rules, a certain etiquette is expected to be followed. Since I don't have anything better to do right now, I'll write up a nice wall of text just for you.
On race servers, this usually means don't midrace join OR stay the hell out of people's way if you're a midrace joiner. There's no excuse for you ruining someone's race if you're not actually part of the active race.
Second, don't be an idiot about blue flags. Unfortunately the rules on this can vary but generally if you're blue flagged (which means someone that's actually in front of you position-wise is approaching from behind) stay calm, don't make any sudden movements to "get out of the way" and don't block any passing manoeuvres. It does not mean you have to remove yourself at all costs ending your race as some people would have you believe, however. Generally a good way to handle this is to run a bit wide into the next corner, so that you can be safely passed on the inside of the corner.
Third, don't drift. This doesn't mean oversteer is forbidden - which would be stupid as it's a part of any race (usually a mistake) - but DO NOT ever
drift through a corner intentionally. I'm aware that with certain setups or in certain rare situations a slight drift can help rotate the car around, keep the engine revs up, etc. but most of the time you'll end up as an obstacle to other racers that suddenly takes up twice as much space and if you get tapped (which happens during racing) it's likely you won't be able to recover since you're intentionally already using up your corrective reserves. Also it is not faster. If you don't believe me, then you're not thinking about the correct timeframe: a race is longer than one corner or lap. If you drift then your tyres will be red-glowing soapbars at latest by lap 2 - beforehand you may have been only slightly slower than regular racers, but once you reach that point your race is de-facto over. You'll never see a drifter win a race because they do not preserve the tyres at all. Has nothing do do with skill but just basic physical laws and common sense.
Of course you don't ever intentionally crash anyone either, but I guess that goes without saying.
Now, drift servers are probably the most lenient in regards to rules. If you race (non-drifting) on a drift server then you're probably no stranger to the short bus, but in any way you'd be missing the point. You go there to drift. Be it drift battles or just general dicking around sideways, what you do is drift, in all forms you can think of.
And lastly there are cruise servers. Universally disliked and avoided by the "grown ups", cruising is basically the drama whore of LFS. Seriously, the amount of tears and wrist-cutting rage produced by these servers is second to none, and that's not even counting cruise vs. non-cruise disputes. The problem here is that the cruising community consists mainly of younger people (since people with driving licenses prefer to do things they don't do everyday in RL, namely racing or drifting), which means more often than not testosterone wins over reason. From the stories you hear on these forums you can expect anything from a relatively chill place to a server crammed full of whining regulars and rampant admin/cop abuse. Just give it a try, you might find a server that you like (they're all different, mind you) and at worst you'll get banned, which in my opinion isn't much of a loss really
