Ok a massive response, let me see if I can address your problems.
Firstly, the words 'I guess' were probably ill suited, the fact of the matter is, these things are more often then not, not black and a white. Meaning that things change depending on the context. As long as you maintain RP as the highest priority and you follow the procedure above then you will be safe from becoming banned.
"~What counts as significant warning prior? If I say "*raises his sword to attack _____" have I made it obvious enough that I intend to fight you? Where is the line?"
I'm assuming you are referring to PvP, so let me make this clear. It should be address LOOCly that you would 'prefer' to pvp. After this the initiation to the fighting should be well noted OOCly.
As for your scenario...
Although this is a difficult situation for you to be in and sometimes roleplaying things can seem tedious or even becoming a disadvantage... roleplay is what is important, if reinforcements are due to arrive then accept this RP and move with it. What is your drive to kill this man infront of you so badly? Try to break his legs and move on quickly if that's what you want.
Writing things with RP
This was actually a rule that was apart of my old rule set, which was sort of editted out of existance... for that reason I fully agree with this as a rule.
Refusing to RP
As stated in this thread, refusing to RP is against the rules and will be dealt with as such, if you clearly do not have the time to RP with the guy, then running away seems like the logical conclusion.