I'm relatively new to this hobby, having had my licence for just 0ver 4 years. About 2 years ago, my local club did a comm exercise using a cross-banding mobile radio. We selected a clear simplex frequency to use and began out exercise. About an hour or so after we started, some hams in another county, unaware of our local exercise, chose the same frequency to have a QSO. When they heard my crossbander ID my callsign, they started grumbling about me "breaking the law" by using an uncoordinated repeater on a simplex frequency. They threatened that they knew CW and the next time my call went out, they were going to write it down and "turn me in." I've been assured by all of the hams in our club that we weren't breaking any laws and that we were operating in accordance with good amateur practice. Fast forward to today. I have the 70cm national calling frequency (446.000) programmed into my scan list and I have NEVER heard a transmission on that frequency. All of a sudden, I hear a weak CW ID break the squelch. I throw my callsign out and a very arrogant ham comes back to me as if he's annoyed with me jumping onto "his" frequency. He informs me that he and a group of hams, ironically from the same county as those who had such a problem with me two years earlier, were working a motorcycle race in the desert with a cross band repeater. I'm confused by this now. Using a clear, undesignated simplex frequency to cross band repeat is "against the law," but using the designated national calling frequency for the same purpose is ok? As a new(ish) ham, I have no way of knowing what "in accordance with good amateur practice" even means.