Today I had a SP call me because my number was on her call display list. I had called her to make an inquiry but had left no message as I knew my privacy would not be readily available to take a return call. An hour or 90 min later she calls me " hi, its Joan Doe", you called me?" Fortunately I was alone at the time and it was not a BFD, but a few minutes either way would have been unpleasant.The offending SP has somewhat of a profile and is a Perb advertiser. I was shocked at her lack of discretion. This happened to me a month ago with another SP. WTF, ladies, you want my number unblocked but you won't respect my privacy?
So, do not call back unless I leave a message asking you to call and providing details of what times to call.
If you have to troll through your call display cold calling numbers you will cause a problem.
Most people who call will leave a message. Even if it is something such as,
"Hi this is (insert name here). I was calling to inquire about your availability, but noticed your currently unavailable to take a call. I will try calling you later as I won't be able to answer my phone."
It's a catch 22 really. Some people will call an SP, knowing their number will be displayed, and expect a call back. Others don't expect a call back. If the SP call's back, it works out. Or, in your case, it might have been trouble. On the other hand, if the SP doesn't call back, often, the pooners get upset and complain that,
"She doesn't call back." or
"Is impossible to book with because she never answers her phone." Just because a message isn't left, it doesn't mean you don't want the SP to call back. I call numbers back if I miss them, and 99% of the time the caller wanted me to call them back and is glad I did.
All you have to do is leave a simple message saying call, don't call, a time to call if you want a call back, or simply say,
"I'll call you another time or later on." It saves both parties a lot of headache. You have to remember, in a 30 minute period, and SP can have 1 to 10 calls come in. If they are busy, it's a pain in the ass at times to get the calls back to make the pooners happy. On top of it, if you look at you phone and see 5 missed calls, and there is a message that says,
"You can call me back, my number is unblocked for you, so you have it displayed on your phone.", how is the SP to know which of the 5 calls was that particular caller? There are 5 numbers to choose from.

That leaves the SP in a situation where there is a pooner wanting a call back, but the SP can't call back because she risks calling 4 wrong numbers.
I wouldn't call it trolling through numbers. I'd call it keeping on top of calls to keep pooners happy. Ten seconds of talking on the phone to leave a message of intention or a request, never killed anybody.

A simple message will save both parties a lot of headache.
Just a thought.