This can't be normal...

I walk past this guy and lady and the lady smiles at me. I smile back.The guy smiles too. I smile back.
Then the guy walks up to me and says hi. I say hi back and he chats me up for a few seconds. I get uncomfortable 'cos there's a lady waiting for him while he talks to me.
Then he asks for my number. I say 'show some respect, you're with another woman'
He turns back to look at the woman and smiles at her. She smiles back.
He says "That's my mum"
I say 'wow!' totally caught off guard. She looks like an older girlfriend or older sister. Not mummy!
I walk up to her and greet her properly. She compliments me.
The guy asks for my number again. I'm not really interested but the mum is watching so I give him a number I no longer use.
Then the mum says "Dial the number to make sure it's really hers."
Hmmmm?
"Is that the phone you're holding?" She asks as the son dials the fake number.
"No, that's my other phone" I reply 
"This number is not going!" The son says after dialing
Yeah, it wasn't meant to.
"Let him have the number to this phone" the mum says pointing at the phone I'm holding
Oh dear me...how weird!
I smile and give the son my real number.
Mum asks son to dial the new number, just to make sure. He does, the phone with me rings, they both smile.
Mum hugs me, son shakes my hand, promises to call. They walk away.
Mum toasting girl for son/making sure son gets girl.
This can't be normal