Good blog, thanks for the write up.
2. If a person receives real money in exchange for their bitcoin they MAY have to register with FinCEN.
I read the "guidance" as being this type of individual would have to register with FinCEN since they would be "a person engaged as a business in the exchange of virtual currency for real currency, funds, or other virtual currency. (depending, as you say, on the definition of 'engaged as a business').
Why do you come to the alternative conclusion of MAY rather than MUST - is it just the uncertainty around the definition of 'engaged as a business'?
Will