After a couple days the fraudster could claim that the wire transfer bounced, take another two days to check with their bank. Then they could say the problem is on recipient bank's problem with SWIFT/BIC code format and pretend to attempt the transfer again.
They might even go as far as actually commission the transfer in front of the recipient but then cancel it in the evening before it's cleared.
Another way to buy some time could be to send transfer for one percent of the amount and then claim it was a mistake with decimal point.
I guess this could be stretched to two weeks before recipients are convinced of the fraud.
As someone who has worked for an american company (I'm not from there and was working remote) and paid by wire, it legitimately happens enough that it would be believable. I once had to wait over a month for a wire to work out (fault was ultimately on my bank's side).
So, yes, an international wire being delayed for a couple of weeks because "issues" wouldn't alarm me enough that I would stop all work instantly.
They might even go as far as actually commission the transfer in front of the recipient but then cancel it in the evening before it's cleared.
Another way to buy some time could be to send transfer for one percent of the amount and then claim it was a mistake with decimal point.
I guess this could be stretched to two weeks before recipients are convinced of the fraud.