Whenever anyone picks up or draws a firearm under any circumstances, he or she had better know the answers to the questions, "why am I doing this?" and "what is it that I intend to do with this thing?".
The answer to the latter may, of course, be conditional.
If those answers are not good ones, that should be a pretty good indication that picking up or drawing the firearm is not a wise idea.
Whether the answers are "good" is not just a legal question; there are the tactical aspects, including those of the physical safety of the actor(s)
Without prejudging the trial or plea bargain that is yet to come, there are two extremely good indications that the Canoles were ill prepared to answer those questions from the legal standpoint. The first is the reported statement "shut up or I'll shoot"; the second is the utterly ridiculous idea that they were exercising their "Second Amendment right."
And then there are the other aspects. As Big Boy pointed out,
....if someone plain clothed was to walk up behind me and point an gun at me, they are likely to be treated with an armed response from me.
And then there is the very real possibility of being detected by first responders who had been summoned by someone else. Let's see--a 911 call about people apparently breaking into a house in the dark, supplemented by a report that two men with rifles had been seen, and then the police come upon a couple of guys skulking around with AR-15s....