Except that the Cessna was at about 1000' and the site is only cleared for use up to 50' with unpowered aircraft.
That is the big problem, people will kick the a*se out of any permissions granted to fly these thing and, on the whole, the sort of people buying them are not the sort who worry too much about rules and regs anyway.
How is the CAA going to get transponders on these when they are not even mandated on gliders or paragliders - both of which I and my colleagues have had near misses with this year as they don't show up on TCAS and are very difficult to see until you are right on top of them.
The big sky theory only works for so long!