Well, on the ALC I heard it often enough that I considered it my name. Aside from a personal greeting, I took it to mean that somebody coming up behind me saw that it was safe to pass on my left and that I should keep a straight, predictable course to allow them to make use of that opportunity, or call out a warning if I saw a gaping pothole ahead I would have to swerve around. Knowing it was my name, I generally kept as far to the right as I could without risking loose gravel or aforementioned gaping pothole or an abrupt edge of the asphalt or a wide-spaced grate, or (rarely!) an even slower rider on my right. Assuming no such reason would make me have to swerve the next few seconds, I would call back "go for it!" or "that's my name" or "on your right!" or "have a nice ride" or "save some dinner for me" or "are we there yet?" or even just "thanks!" That way they knew I'd heard and understood the warning. Also I got a nice wave or a laugh, which made it kinda fun to be the slow gal on the route.

Now as for those two guys ... Well, they were rude, but the rules of the road do still apply, and the general traffic rule is that it's the person passing who's responsible for being sure it's safe to do so. If it were me doing the passing, I'd have stayed behind them a while, then maybe called out "Guys! There's lane enough for the three of us and I want to pass. If you'd move over, I'd pass on your left. You wanta stay like you are, I'll pass between you. What's it to be?"

Oh, and if this were ALC, where all 2000+ riders are under strict orders to stay single file except when passing, I might report them for creating a dangerous and irritating situation.