You can actually agree on something for the escort to say when calling.

I usually deal with high end ladies(be selective when giving work info) and usually they have that 'secretary' tone of speaking and manner of voice. (Think of Joan from Man Men)  we agree on the story that she should say she is callilng from the dentist office or somethig generic and boring like that so that noone wonders why I got a call.

and that they are calling to schedule me for my next photo shoot.

You'd be surprised how quickly rumors start to spread around an office after that.

Often times they will just ask for you and when the switchboard operator rings your extension, they will hang up before you answer.  Now they know you really work there and are not likely to be LE.

They might use the dentist, doctor, office excuse as has been mentioned.  They are just verifying what you told them for safety.

Swim

thanks for the info everyone