Some close encounters may look entertaining with hindsight, but all power pilots flying near or over active gliding sites must be aware of potential hazards. Same as skydiving sites, especially operations out of mixed activity GA airfield.
True, mishaps can happen and it's not just the open airbrakes stuff.
Canopy popping open at the wrong time, diverting the attention of surprised early solo pilot can easily cause accident. Just like the one I heard of last summer, while ago in the US, where the tuggie didn't make it.
I don't want to scaremonge, but whoever decides to do tugging, must be very cautious, especially with early solo pilots at the back end of rope close to grond and first 500 ft or more.