There is the additional worry that if this broom handle pounding is performed that you will be providing a readily accessible spiked club with which one might be, how shall I put it, persuaded of the error of one's ways by an irate spouse, partner, or owner of said hardwood floor, so maybe we should just be content with the one hat after all.
Double-glazing salesperson: "I just want to ask you - if you could have any room in your house double-glazed for free, which would it be?
Self: "None of them, but thanks for calling." [Click]
Financial services salesperson: "Do you have a couple of minutes to take part in a customer survey?
Self: "No, but thanks for calling." [Click]
Door to door religious salesperson: "Can I interest you in the word of the Lord?
Self: "No, but thanks for stopping by." [Click]
I find that the little gesture of politeness catches them momentarily off their guard and enables you to put the phone down or close the door with a clear conscience and without leaving an opportunity for comeback.
Meanwhile, I wish the person calling the phone in the next office would get used to the idea there's nobody there...