In general a Fellony robery charge should trump a Misdemeanor charge...  but a lot depends on your local Police.  Some will view this as the dangerous incident that it is.  Others will think you had it coming.  

Do you think the provider was in on this?  How is it you know her realitives?  These activities should be encapsulated...  She should not know too much about you nor you her.  She should be told that this occured & you'll not be seeing her again & why.  A lady works hard to establish her reputation as an honest provider...  if her clients get robbed because of her, this destroys the reputation she has worked so hard for.  
Where did this robbery occur?  At her location?  on the street?  your home?  a hotel?
Frankly, this is one reason for prefering incalls at a hotel.    
I'm sorry this happened to you.  
skb

because they know the seriousness of collaring an armed robber before someone gets killed.

In any case, the solicitation charge is not even the biggest threat facing the client in this case; it is the exposure to your wife, friends, co-workers, etc. once the incident hits the news. (Which it will, believe me.)

For that reason alone, I would not hold it against anyone if they did not report it, but they should report it on their local board lest other unsuspecting clients similarly get ripped off.

(still not a lawyer)

Without fail write a factual reveiw to protect the rest of us!!  Then:

1.  Do nothing official.  You aren't getting your funds/watch/whatever back anyway.  Chalk it up to experience and walk away.
2.  File a less than complete report to support an insurance claim - risking an (unlikely) misdemeanor charge for filing a false report.  While they might not believe your story of being someplace for a legitimate reason, unless you so state otherwise, they can't PROVE your story to be false.  Not really a recommended course of action
3.  File a complete and honest report.  Unless you live in East Podunk or unless  you are personally prominent, this level of crime isn't going to make a ripple in the local news.  Ask the officer taking the report to assure you that you are not waiving your protection from self-incrimination by making the report.  Like as not they would rather know about the thugs than try and use your own statement to prosecute you for a misdemeanor.  
Just my very amateur opinion
MVR

if you were robbed, you were robbed, you need say no more than that you were in the area (if asked why, just say visiting someone).  Unless the provider was in on it, she is not going to volunteer info.  The only reason not to report it is if the location is in an area you'd have a hard time explaining.