Eric Greenwell wrote:

"Can't that happen in broad daylight to a VFR glider? At least the IFR
glider would have a transponder and be in contact with ATC. "

I researched this years ago and concluded that, as the holder of an
airplane instrument rating and a glider rating, I could fly a suitably
equipped glider in class G airspace, in cloud, without an instrument
flight plan, without a transponder, and without talking to ATC.

I interpreted suitably equipped as meaning the instruments required by
the type certificate for cloud flying (ASW19b std airworthiness).
Experimental certificates may include different restrictions such as
day VFR only.

The reason for much class G airspace is that there is no radar
coverage. I had identified a suitable area near Bagdad, Arizona.

No I didn't do it as I didn't want to buy a gyro and then have to
remove it for contests.

Andy