Short of an chair breaking, spilling you backwards and upside down where your cover garment is overturned I have a hard time buying most flashes are anything but lazy packers who are not serious about concealing for whatever reason they may have.
I sh## you not, there I was sitting in this chair when......Just kidding
I was in a Target store shopping with my young son. I was a new LEO, but was taught from the beginning to always carry off duty. I was bending over to tie his shoes and my weapon must have printed through the t-shirt I was wearing. I stood up and continued to shop when I felt a hand on my gun. I pinned the hand and took the hand's owner down in a straight arm bar. I then realized that I took down one of the security guards who thought I was trying to shoplift. Felt bad about it and was embarrassed, but learned a good lesson. Shop in Wally World.