Faster Than Light, no Left or Right

In the Voyager episode Fury (Season 6: Episode 23) Tom Paris said that the first thing new recruits were taught at the Starfleet Acadamy, "Faster than light, no left or right."

This quote has been mentioned by the Star Wars side many, many times. But what does it mean.

There were four competing theories presented: Note: Not all theories presented had support, some were just given as alternatives.

1. They can not turn under any circumstance, it's against the laws of nature: This is false because we've seen them turn at warp, although not often.
2. They can not turn cause it's against the Federation law: This is just plain stupid, but stupidity and Star Trek seem to go hand in hand.
3. They can not turn cause it can causes [Insert Technobabble Here]: However, turning can be done in desperate situation, because the results of turning at warp are not as severse as, for instance, Borg assimilation.
4. While traveling faster than light, a ship cannot turn faster than [Insert Complex Formula]: Recruits are just told 'Faster than light, not left or right.' because it is easier to remember.

The most likely correct theories are 3 and 4, or a combination of those two, (Turning faster than the complex formula allows can result in dire consequences. But those consequences might be the lesser of two evils in a desperate situation.) However, some debaters like Robert Scott Anderson felt that Theory 1 was the only possible explanation. And since there are contradictions to that theory the quote must be thrown out and turning at warp speeds can be done without restrictions or nasty consequences. This is, of course, completely wrong.