Presumably, your phone would say something like. "The person calling you is using a google service to listen to hold music for them... they should be with you momentarily."
I’ve had Brands interactions on Twitter where they ask me to go into private, then ask for my phone number, call me and send me directly to a holding queue, i guess it would fair to respond in kind.
Exactly the sort of behaviour I'd expect from a company that considers "brand interactions" to be a thing.