Very true. Many studies say the signs are the best deterrent.
As are REAL cameras that are plainly visible on the outside.
I rebuilt my fence last year, moved it up from the rear corners of the house to the front which obscures my garage side door from view and makes less of an invitation. Solid fence that is 6 foot tall and gates on both sides are locked when not in use. It would be pretty obvious to any neighbor that something was up.
Bonus is we live 4 houses into the neighborhood at a three way intersection- which is bad for traffic at times, but keeps the house under constant view. Neighbors next door work from home mostly, across the street is home 24/7 and elderly couple across next to them doesn't miss a thing. Always felt a bit more comfortable that we'd make a poor target considering we are home most of the time... Anyone casing the joint with half a brain would avoid it.
So location, location, location and multiple perimeters and preparation means that you likely will never have a bad guy trip the alarm... But you might someday get the stupid one.