I threw 3 Puppia step-in harnesses in the garbage! ZoE can easily escape it and did so in my front yard (I live on a main road)
I figured I'd put the harness on wrong, so took her into the furthest part of my back yard (I'm on a few acres) and tested is again. Once more, she slipped right out of it by turning around to face me and quickly backing up. The harness slipped right over her front legs/shoulders and off her head. Into the garbage they all went that night! (I do have two regular Puppia over the head style harnesses, and I've never had a problem with them, other than ZoE outgrew them).
We now use Buddy Belt harnesses and haven't had a single escape issue.