Only Civil Servants would want to crowd air traffic into narrow airways when nowadays [with seriously accurate navigation systems available] aircraft could file their intended routes as they were taking off and a computer could calculate in advance any potential conflicts. That plus inbuilt proximity warning systems should help safety. 100% safety is frankly impossible, only the present PC biased expect that.
That is for the big boys however. For the minnows [who mainly fly VFR for fun only] Mode 'S' is a real pain in the ar*e, literally, as our gonads are rarely more than a few feet away from the transmitter aerial [200 + watts]. Sophisticated sailplanes will have to carry less water and more battery power if they want to cross airways IMHO.
The thought of bimbling PowerChute pilots at 1000 feet sitting on Mode 'S' gear seems utter stupidity.
BTW Not only Sailplanes win World Championships - UK Microlights do too!
a sample
http://www.czechinfo.aero/wmc.aspx?lokID=2