[shabble]

A 'marriage of convenience'[1] in that sort of situation is typically treated as fraud, with potentially high penalties (deportation for the incoming, jail for the citizen). I've heard from more than one recently married couple that they've been separated and intensively interviewed about their personal lives, marriage, and backgrounds. IIRC one was returning to the US, and another was entering Canada. In both cases one of the couple was a native citizen.

If that were the actual reason, I'd be surprised if there wasn't a standard form letter or actual reason for denial. I suppose 'Go Away, We Can't Talk About It' might get used in marginal cases or when the appropriate authority can't be bothered doing the actual research.

Or they just lost at Top100 Terrorist Names Bingo.

[1] https://en.wikipedia.org/wiki/Marriage_of_convenience