I must take my share of the blame there. Static towing is indeed a different thing from winch towing & Was banned by the BHPA years ago, folliowing a spate of accidents - all lockouts!
To answer P Monke's question, there are strict rules around towing in the hang & paragliding world - in the UK at least. Tow operators have to be trained & endorsed. Pilots can't just rock up & start towing, they have to take a course in towing too.
Winch lines have v-bridles & weak links for saftey, but as with any regime in flight, there is always scope for pilot or equipment failure. I think the consensus over the towing argument is that each individual situiation will work on it's own merits & whilst any fatal accident is abhorrent, they remain, thankfully a rarity, but there are probably no stock answers on tow failures per se - only guideline procedures for a given scenario. Every PIC is just that - in control and thus responsible for their own actions.