Many air carrier aircraft now emit ADS-B which makes their position visible to PowerFLARM. Before PF I had three interesting encounters.
With PF I catch them 10+ miles away.
Transponders are battery hungry; very few gliders have the capacity to always have one on.
Class E is a hodgepodge airspace. Yes there are approaches used maybe half a dozen times a day. Do we really want to make them all Class B and C and shut down the many airspace users for a very few movements a day?
Oh yes, the local IFR frequency is never published on VFR charts; so how can anybody expect VFR users to know about IFR traffic.?