Canopy opening in flight

I once towed an ASW19 with an unlocked canopy, no dramas but
the glider pilot (post flight) described the canopy sucking partially
open then dropping before sucking partially open again. Using his
elbow he was able to temporarily secure it until we got to a height
that allowed him to release and put the canopy locks into the
appropriate place.

The additional (near) airprox with an R44 at about 400ft during
climbout was far more exciting!

At 11:35 26 August 2018, Tom wrote:
Anyone know of an occurrence of a forward hinged canopy that
opening in
flight? Any possibility of this happening if the forward hinged
canopy was
unlocked on a flight?

Thanks Tom