I think it is a good idea.
My twist on this was to use a DC linear actuator in the tail that took power direct from the wind turbine to activate it. High temp closes electrical contact (look up KLIXON) connects turbine output to rectifier, from rectifier to actuator, tail is forced to furl. All of this could be located up on the turbine.
If this did not work, then same circuit but use a DC cable winch at the tower base to activate a cable furling setup instead of linear actuator. A number of commercial wind turbines have the cable furling arrangement, but it requires slip rings....should still work.
The neat part about this safety feature is the fact that you could put a high voltage latching relay connected direct from the turbine. Once a overspeed was created the voltage would be high enough to trip the relay, the contacts would be in parallel with the KLIXON contacts, and "force furl" your turbine.
Essentially you could have both an overtemperature, and overspeed fault protection that would cause a furled condition for protection, and would not require an external power source. The gravity furling tail would still be needed for regulation, this would just be an extra measure of protection, in case of an abnormal condition.