Head nod to dealer a check?

[dibbs]

It's on you, the dealer is looking at you waiting on your action, and you nod to the dealer in a "yes" fashion while making eye contact.

Is this a real check? Most dealers in this game casually accept it, but someone decided to play an angle which ended up in bickering with arguments such as "you have to nod and point for it to be a check" and on and on.

So, whats up with this?