rules get broken everyday all the time. yeah wtf do i know i only traded prop and dealt with big banks for years. its not enforced! just because you drive 100 mph in a school zone doesnt guarantee you get a ticket if no cop. how many idiots does it take to understand the free mkt is just that full of all kinds of rule breaking bending and outright lawlessness. the big ones dont ever worry about it..its nothing.
I work in a professional trading setting and this was never the case in my experience. Many trades require shorting and locating equities and we certainly paid attention to Reg SHO.