I've been meaning to ask: If an aircraft is susceptible to tailplane stall, is the stick shaker/pusher active for that condition?
This question assumes that manufacturers and type certification authorities would accept a type design that was susceptible to tailplane stall. Tailplane stall has never been considered an acceptable condition, so I would be very surprised if any manufacturers had considered designing a stall protection system that envisioned possible tailplane stall.
In the past, tailplane stall was not formally considered in the design or certification process. That changed as a result of several DHC-6 Twin Otter ice contaminated tailplane stall accidents and incidents. DeHavilland and Transport Canada were very surprised and concerned by these events. They addressed the issue on the Twin Otter by an AFM limitation prohibiting use of full flap after flight in icing. For future designs, now that the issue of tailplane stall was recognized, Transport Canada mandated specific flight tests to no susceptibility to tailplane stall. These criteria were applied to Canadian manufacturers, and to foreign manufacturers that wished to obtain a Canadian type certificate. Eventually, the other authorities adopted similar tailplane stall criteria.
Now days, any type that receives a type certificate from any of the major airworthiness authorities should have received a comprehensive flight test evaluation for susceptibility of tailplane stall, and any design changes made before the type design was issued. Even older types with tailplane stall problems (e.g. unmodified Saab 340As) should have had Airworthiness Directives that required either modifications or AFM changes to address tailplane stall. In theory, if flown in accordance with the AFM, none of the major Transport Category aircraft types in service today should have a susceptibility to tailplane stall. I'm not sure what was done with some of the less numerous types though - are there any Viscounts still in service anywhere?
Some stick pushers are inhibited at airspeeds greater than XXX kt, but this is done for structural reasons, not because of tailplane stall.