The 3rd rule is something we look directly for when hiring. If there is a direct passion (ex. Edtech) to draw from, it makes the candidate stand out from all the other "iOS dev" "DevOps" etc
For companies that are trying to "recruit" you away from your current employer, they are already aware I would assume.
Also, it seems like it would be make sense to deny an offer/opportunity if it's less than what you're currently making and/or vesting value.
I do agree that the counter offer strategy is not always a guaranteed win - I was more curious about people using this as a way to find out their "market value" (what someone is willing to pay/offer you)