Do promoters see a band just bringing amp heads just as useless as bringin fuck all?

I've never worked with a venue that had cabs but many bands turn up with hamp heads and I have to hire cabs from somewhere else.

Talking to others they say all venues should have the cabs but I have NEVER worked with a venue that had spare cabs lying around..only some battered combos.

So where does this idea come from that all venues have cabs that you can plug your amps into?