I have never heard of such a thing.
Furthermore, "you want me to what?".

Ya, you sell/close on the house when it is complete.
That is after the wireing-HVAC etc. is done.
Someone must cut the holes.

Tell him you'll be back when thats done.

Move onto the next one and see if you can "squeeze" him in.

"NO TIKEE, NO SHIRTEE"!

No wires,no sale.