I think a lot of that advice comes from dealing with LEOs in "hostile territory." For example, if you open carry in Las Vegas, where Metro was (and often still IS) openly hostile to most forms of carry, you can expect to be hassled. The same was true in Cali prior to the outright ban on unloaded open carry that took place this year. I suspect that if SC allowed open carry there'd be at least a few jurisdictions/departments hostile to citizen's rights, just like those in NC and FL that try to buck pre-emption. In those jurisdictions you must know your rights, know the law, and protect yourself by recording interactions and/or having a good witness present. These sorts of tactics have been effective in other places in getting LEOs educated about 2A rights and changing the behavior of the department. These tactics also protect the citizen having the encounter.