Can you please clarify your hierarchy?
You say you have 45 sites. Does that mean you have 45 secondary sites or are you using "site" generically to mean location?
You also noted "At their site, I gave them an MP and DP." Adding an MP or DP is not optional with a secondary site so clarification is definitely needed here.
Note that if you are in fact using secondary sites, that clients within the scope a secondary site still use and are assigned to an MP within the primary site. This is because MPs at secondary sites aren't full MPs and few smaller and very sporadic operations must still be handled by MPs within the primary site. This includes initial client registration.
So the additional question here is what exactly is leading you down the path of this question? I'm not saying it's not a valid question in any way, but when you say "clients are still coming across the wire to connect to a remote MP" that's a generic description that and not a technical one so it's difficult to explain a behavior at a technical level when we don;t have a technical description of exactly what you are seeing.
+1 the others comments as well.