Oliver
All, after just having had the misfortune to rip my roof canvas in the scissor hinges, Hazy Dayz coincidentally sent me this email about a new product to prevent this from happening. Can't vouch for the product but sounds like a neat approach to a common problem.
http://us5.campaign-archive1.com/?u=3faf7129d5a5baf43c5925eec&id=7248ab7e03&e=35cbaee7c1
http://us5.campaign-archive1.com/?u=3faf7129d5a5baf43c5925eec&id=7248ab7e03&e=35cbaee7c1