https://en.wikipedia.org/wiki/Ignorantia_juris_non_excusat
Ignorantia juris non excusat or ignorantia legis neminem excusat (Latin for "ignorance of the law does not excuse" or "ignorance of the law excuses no one") is a legal principle holding that a person who is unaware of a law may not escape liability for violating that law merely because he or she was unaware of its content.
This is applicable
if a person is claiming they did not know that such a law exists,
but we are talking about a person who knows the law exists. It is impractical or even impossible for a person to apply the 51% rule unless, as GreyGeek commented, the owner publicly posts his financials.
As I said in my example, if a person gets cited for carrying in an establishment that sells
only peanuts and alcohol, they would have a losing argument. Much in the same way a person can argue in a SD situation that a "reasonable man" would be in fear for their life and warranted in using deadly force, a reasonable person may not have any way to discern which establishments are off limits.
Fly