I once saw a boat with the "cone" painted on each side of the clew of the jib/genny.Pull a bit of foresail out=instant cone.Good idea or not(not in my case as I am not painting on my nice laminate sail)
Lets face it, the rule is not a bad one.
It is just that it is a pain to rig often for very short periods and it can be damm right dangerous to rig at times.
If a good, quick, easy way to put one up is thought of more people might use them. A pop out cone in a very small tube or the like which can be pulled in or out from a line in the cockpit.