I had a male student for about a year. He was actually a pastor. I was careful in scheduling his lessons at first, but after I got to know him better & trusted him more, I let him come at whatever time suited him. He ended up quitting b/c he didn't have time to practice like he wanted, and even though it was a little weird at first (as he was my first beginner-adult student), we developed a good rapport. I did not ever feel unsafe or creepy with him.
Sounds like you have a good plan, CJKitty. Hal Leonard adult method is kind of nice, and it comes with CDs. I don't remember if Bastien adult comes with CDs... it seems that some adults like the opportunity to play along with the CDs, to confirm that they're "doing it right".
Anya, I'm so sorry you've had to deal with so many creepy people - and mean/demanding people too!
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