Why does Clarence need space to plant a transmitter on somebody?

Question

In Oceans Eight (2018), Debbie and her team, who are about to steal a necklace from Daphne’s neck at the Met museum, are discussing the robbing plan:

Lou: And once we get the Toussaint, we are gonna have to get it out of there without being detected, and they're gonna go over their security footage with a fine-tooth comb, and anyone seen exiting that bathroom is gonna be a suspect.

Debbie: So...So we get a mule. Somebody else is gonna move it for us. How much space do you need outside that bathroom to plant it on somebody?

Clarence: I don't know. Nine feet?

Why does Clarence need space to plant a transmitter on somebody?

Answer 1

They weren't planting a transmitter on someone.

DEBBIE: And how long is it gonna take us to build a nine-foot blind spot?

9 BALL: Moving a camera?

DEBBIE: Mmm-hmm.

9 BALL: Bit by bit, 10, 12 days.

They planted the necklace on a busboy's tray who then unknowingly passed it on to Amita. They needed a nine foot blind spot in the security camera coverage so the security camera couldn't see this happen.