Are you saying that MFS will not allow a private connection between two routers located at the MAE facility, even if the connection is _not_ made using the MAE FDDI switch, but is instead a direct (e.g. HSSI or AIP) connection between the two routers?? If so, I haven't seen any documentation to that effect...
MFS has nothing to do with this. The issue is using the shared Internet resource (namely the GIGA Switch) to connect customers. The original members of Mae-East aggreed to this when we set up the first peering sessions. The exchanges are for peer to peer traffic, not customer to vendor traffic.
Note that this differs mightily from the DEC NAP that I've been helping to create down in Palo Alto. There are four GIGAswitches (two FDDI and two ATM) and it is very much expected that some folks will buy colocation space from DEC and cross-connect over to their transit provider du jour. Someone who just wants to put their servers close to the "backbone" should not and will not be connected to the public GIGAswitches. Running transit routers and doing all the BGP and RADB work to get peering working and keep it working is much too complicated for the average server owner.