If you haven’t seen it, you should check out the Cant Dictionary of Thieving Slang, 1737:

ANGLERS

ANGLERS, alias HOOKERS; petty Thieves, who have a Stick with a Hook at the End, wherewith they pluck Things out of Windows, Grates, &c. Make ready your Angling Stick; a Word of Command used by these petty Villains, to get ready the Stick with which they perform their Pranks, and as a Signal of a Prey in Sight. In the Day-time they beg from House to House, to spy best where to plant their Designs, which at Night they put in Execution.

It’s a classic.