Huge error for me.
The offending player's reaction (hand up immediately in apology) should confirm to the ref that it's a "bad one" and a red card is required.
As other's have said, this is one of those videos shown at CPD events and everyone says red card
I have to disagree with the bottom line because I think I've been to many CPD events and it's extremely rare that everyone agrees on anything! I can accept that a large majority would say red.
Additionally, and I know what you mean by it so please don't think I'm being funny, but just for clarity, I wouldn't ever use a player putting his hand up in apology to tell you something's a red card offence.

