Allowing a patron to enter a bank with high explosives is trusting the patron with your life. I can't think of a single person I would be happy to welcome in my home/business with high explosives or a firearm, but would refuse to take $20 from in my ordinary course of business offered to the general public. Perhaps the correlation is not 1:1, but it is pretty high up there. If you can't see the connection between trusting someone with your life and trusting them with much smaller fractional pieces of life, like an hour's worth of life it may take to earn $20, then I'm afraid I don't expect you'll ever see the correlation and you are not part of the audience which I expect to benefit from my comment.
>The two have nothing to do with each other.
And yet they do have something to do with each other. If they had absolutely nothing to do with each other, you wouldn't become a prohibited possessor (can't have/carry guns) for committing bank related fraud and other account related felonies. The state has decided they're connected so intensely that you can go to jail for 10+ years if you committed felonies against the bank and then carry a gun. The trust, by fiat, is interconnected.