By that argument, we would have to boycott everything anyone with a disease ever touches - hard surfaces (virus is known to survive for up to a week) such as train rails would be tricky one - since we would have to send it back to the manufacturers with every suspicious contact?

I think cash has been known as dirty for a while now. There are ways to manage infection, without boycotting i think - with things such as washing hands frequently being sufficient in many cases.

"No evidence of that" is a valid argument.