I've recently observed with the SMT (remotely). It's a good telescope and you all do a great job running it!
(it seems that gasoline station owners here in Massachusetts got a different memo, though)
Despite the fact that the outcome is similar, there's a legal difference between "surcharge for credit" and "discount for cash". The former is/was illegal, the latter is legal. Presumably gas stations in MA and elsewhere are doing the latter.
Every nonzero finite dimensional inner product space has an orthonormal basis. It makes sense, when you don't think about it.