Mark James Boyd wrote:
I also heard rumor that
commercial glider pilots used to be able to give
glider instruction to students. Is this true?
How long ago did this change?

I have also heard this. I suspect it must have changed during the early
'60s. By the time I started taking glider lessons in the late '60s, a
CFIG was required. Back then, you did not need to have a commercial
license to become a CFIG, unless you wanted to get paid. I actually
received instruction a few times from a 16 year old CFIG (I was 15 at
the time).

Marc