Hmmm,
quite the lively discussion!
One thing seems to be apparent. That people believe it's more acceptable to "backstab" in a RP situation. I can understand that, you're "fulfilling" a race's expected actions. Though not getting involved in any RP SE games, I would suppose all players in such a game would know ahead of time (by race descriptions or something) the nature of the race they may be dealing with. So, you might have an inclination of just how much someone/some race had to be "watched".
On the other hand, in SE games with no RP, I think most of us are referring to making treaties (and such) with the first players we encounter. The treaties and agreements aren't RP aspects, they're tools to win the game. And, as was said previously, if a player has made agreements and then somehow taken advantage of you in an underhanded way, I think everyone "takes that to the next game" to some extent.
For you, Pax, I suspect you remember previous "backstabs" but perhaps that's as far as it goes with you. Others, I suspect, me included, also remember those who have "backstabbed" us (or possibly others). For my part, I don't make treaties with that person again. It doesn't mean I hold a grudge and will immediately attack. It just means I believe the person is less trustworthy than some other players I may encounter and I don't want to place myself in jeopardy again. Others may try again (or not). Still others may decide the person needs to be attacked. (and certainly in a multi-player game, where an empire MUST find someone to expand against, those who have done "backstabs" are usually near the top of the "hit" list
)
Winning? Different definitions? Perhaps. To add a bit of levity, I'll throw in an analagy using something my sister told me once about sex (and size). She told me when a guy had a big "one", THAT was good. When a guy knew how to "work" it, THAT was good. But when a guy had a big "one" AND knew how to "work" it, it didn't get any better than that! So, to Pax, I'd say, "When you roleplay and have a really interesting game with all the interaction and such that you hoped for AND win the game, it doesn't get any better than that!" That's my way of saying I think there are various levels of winning.