Sad but true: there are people out there who will steal you blind if you let them.
It occurs to me that I see many garagesales set up with no real security in mind. I’ve seen cash boxes sitting open on a table with no one in sight. I’ve seen cash boxes left on tables full of garagesale merchandise, and the homeowner off talking to someone and not paying attention to it. I’ve seen people leave small children manning their own table, with cash boxes stuffed full of temptation for the unscrupulous.
Cash boxes aside, I’ve also seen some expensive pieces of jewelry and other pricey items left towards the bottom of a driveway where anyone could grab and walk off quickly.
Personally, I don’t like cash boxes, because they’re too hard to manage when you’ve got a bunch of people rifling through your wares and distracting you. Better that you use a fanny pack, and actually wear it, so your cash goes with you and you don’t have to stress over it.
For expensive items… well for one, don’t sell them at garagesales - you won’t get what they’re worth. Consider private sale or an auction house. However, if you just want it all done at once, so be it. Keep those items up at the top of your driveway or in the back of your garage (wherever you’re doing your sale) and in the center of the table where people need to be obvious when they’re looking at them. I’d also post someone on that table to keep an eye on things.
Sure it’s a garagesale, but these things still belong to you, they’re worth something, and it’s worth a few extra minutes setting your sale up to prevent problems like this as much as possible.