If I buy a CD and play it in my home, how many others may be in the same room listening before I need to pay a fee?
There is a legal number which may be different in your jurisdiction, I seem to recall that the legalese for my jurisdiction at the time was something like, "If they are paying you anything, you can't have more than 12 or it's a public performance". I got nervous when my church played a recording of a song, but as I understand it, there is no customer-business relation between a church and its minions, they aren't paying to be there.
If a company buys a CD and plays it at their place of business, who else may be in the room listening before they need to pay a fee?
If RIAA thugs can walk in, pretend to be customers, and can hear your music, you are probably getting sued.
I do not know the answer buy my personal opinion is "as many as I want" unless as a business the main reason why customers are paying me is to listen to those specific songs, in that case I am re-marketing them.
The laws are messed up. Complain to your congress-critter. But first, give him the complimentary, indefinite use of a yacht and a beautiful blonde (of the gender of his preference, obviously) and 'forget' a couple suitcases of cash in the yacht that he might find.