Scenario #1 - A worse case, there is a record of you making a call. There is a recording of your call.
YOU - Hi is Mary available at 3:00?
SPA - Yes...
YOU - Great I'll be there to see her at 3:00.
Exactly what does the prove? What crime and laws have been broken? What are you going to get charged with? NOTHING - Even if they had video of you entering the building that proves nothing as far as what actually happened in the room. Now if you own an NFL franchise and decide to drive your Rolls to the Spa, expect to be black mailed and exposed but even then they really didn't have anything they could charge him with that would stick.
Now you understand why they don't answer questions over the phone, when you start asking how much for X, Y and Z.
Scenario #2 - You start talking to LEO and his friends. They scare and intimidate you (yes they can be scary) into opening your mouth and you start answering their questions.
LEO - We have a recording of you making a call to this place. Your wife is going to leave you. Your place of employment is going to fire you. Your in big trouble unless you tell us everything (they are allowed to lie). We can help you (another lie) but you have to tell us everything.
YOU - Poo your panties, start crying and confess to everything.
LEO - Thanks for self incriminating yourself and doing our jobs for us. You have the right to remain silent...
Your Lawyer - You idiot, why did you open your mouth? They had no evidence against you until you shit your pants and confessed to everything. My rate starts at $200/hr sign here.