Using other freqs to communicate between planes or ground?

Dave S wrote:

Given the small amount/number of frequencies, I doubt that you have
exclusive use of YOUR frequency.

I put the word "our" when mentioning the frequency in quotation marks
because I *don't* know if it is registered to our FBO with the FCC ...
it is on all our documentation as our "base station" frequency, and it
is also listed in the Flight Guide (which I realize doesn't necessarily
mean anything).

There should be air to air frequencies
and Multicom (122.9) for air to ground that should be used for such
purposes that the "unwitting pilots" are using them for, but that being
said I doubt that any FBO has standing to claim a frequency for
exclusive use.

Maybe my term "unwitting pilots" was out of line...I expect a pilot from
out of the area may not know it's used for our FBO without having
specifically looked at our info. And no, we don't try to "shoo them off"
when we hear them; however, we do tell them that they are chatting on
our aircraft-to-FBO frequency. I've yet to hear any conversation on that
frequency *between aircraft not from our FBO* that consists of anything
other than "hey Bill, what time did your wife say you had to be back
today?" or "I'm over Dead Tree Road, where are you?" ... and when we
tell them they're on an FBO frequency, they pretty much tell us to
"f@#$-off" too, just as another poster said.