I'm not so sure this wave of SYG legislation is good policy - the law of self defense works pretty well in most jurisdictions, and did before SYG. In my view it offers little to no additional protection to law abiding citizens, but a fantastic loophole for underworld types to avoid facing juries and instead have their cases dismissed by a judge. Drunken bar fights, gang fights, etc seem to be the most common invocations of stand your ground laws.
Na.
No person should have to retreat from their home, business, buddy's place, etc. It'll be pretty easy to tell the scumbags from the regular citizens. Guy who I halted from trying to steal my car stereo had a list of crimes that was about 7-9 pages. I am the owner of my property, have no documented contact with the guy, and no criminal record in the US.
Thankfully, I did not have to use lethal force. But I doubt the legal end result would have been much different. It did, in part, come down to his word against mine. I'm not saying one's history should be the sole criteria used, but unless it's scumbag on scumbag crime... Most times it is the most obvious scenario. If a person with a lengthy criminal history is shot on the property of someone without a criminal history, the person without a lengthy criminal record is probably not the aggressor.
If two folks with lengthy criminal history engage in lethal activity, yes, trusting either party may be very complex. As long as no innocent bystanders are injured, few folks are going to be overly concerned.