Exactly this. As a British English speaker that works a lot with the US it was an early learning. In British English a "scheme" has no negative connotations. I

Exactly this. As a British English speaker that works a lot with the US it was an early learning. In British English a "scheme" has no negative connotations. It's commonly used in all kinds of legitimate places - for example the company you work at will have a "pension scheme". In U.S. English it has a connotation that it is nefarious in some way.