Yes agree on a physical lock for the lens release button. Or an option to have to press the focus preview button at the same time to release the lens.
I often cover weddings, events and have somehow released both 70-200 m2 and 28-70 m2 lenses by accident. I am often holding the camera in different positions, above my head pointing down, from below, side etc. Canon, please create an additional lock or safety measure!