Why? People call businesses all the time and get robots, why would it be different the other way around? As soon as the boss figures out you're hanging up on people trying to get reservations you can bet hangups will stop ASAP.
Most of us hang up on robots too though. Robocalls are a nightmare. The best argument against Duplex IMO is that it’s going to enable a new generation of hellish scams and robocalls, if it ever leaves Google. Presumably Google knows this and will keep the tech locked down. Still, it’s only going to be a matter of time before it’s open one way or another, and then we’ll have to have the “should I be told up from that it’s a robot?” conversation again.
Most of us aren't paid to answer the phone though... If my job was to answer the phone for people making reservations and I started to hang up on reservation bots I would expect to be fired immediately. I also hang up on real people who call me unsolicited for sales pitches, it's not the bot part that annoys me.