Thanks for the responses! As my local Arthur Murray has taught me, my normal step method is to step LF to the left on count 1 and then RF back on 2, and I reverse this to RF to the right on 1 and LF forward on 2 if the girl steps back normally to start the basic.
Onlooker, I hear what you are saying and I am willing to step as she wishes. Afterall, I will rarely if ever again dance cha cha with her anyways. I could save the proper basic timing for the more educated dancers. I am beginning to think that I should just ask a girl how she likes to step as we take our dance position at the beginning of the dance.
One male instructor at the AM studio, who competes professionally, recommended to me that I try to continue to lead the proper timing, but strive to achieve a good connection with the girl before taking that first step.
I did speak to the local club instructors (fantastic Salsa dancers and partners themselves) who had a cha cha group class a few weeks ago at the same local Latin club. The crowd they taught was primarily a Salsa crowd. Prior to that group lesson, the dance floor used to clear when a cha cha song played. They taught the LF forward step on count 1 but acknowledged the Mambo origin and admitted that there are many songs where it would be better to wait till the 2 count. I did thank them (with enthusiasm!) for teaching all the Salsa dancers some cha cha basics. Afterall, the dance floor no longer clears during the two token cha cha songs the DJ plays each Latin night.