Keep refreshing this page and eventually the answers to your questions will come up…
Anyhow, I second the prickly hedge option. Hawthorns, roses, prickly pear, whatever. Most people won’t risk their skin or their clothes to steal plastic flamingoes, and vegetation is generally less grim-looking that razor wire. If you don’t want to buy hundreds of plants you could just set up a few short (3-foot or so) posts, string plain wire between them and train rambling roses along the wires. Might take a couple of years to get complete coverage but it should give people the general idea that your yard is private property without looking like a penitentiary