Why not have the panels disconnect themselves in this case? Is this too small an expense to justify the cost of additional hardware to manage switching on and off?
It all depends on the situation. Here in the Netherlands almost everybody has an PV installation with no way other than the breaker to turn it on and off. Some inverters do have an interface, and sometimes it's available. Even less people know anything about this at all, they just had panels installed. The technical solution is simple, bit implementing it will cost much more, I assume.
Why not have the panels disconnect themselves in this case? Is this too small an expense to justify the cost of additional hardware to manage switching on and off?