I always fear this happening...when I go to the range, it usually takes a few trips from door to truck with cases, cans, etc. given our over criminalization I don't want this to lead to a search that, even though I do everything possible to make sure I haven't done anything illegal, could turn up something and cause legal problems.
If someone calls the cops because I'm carrying CASED weapons and ammo cans, THAT is a problem.
In this case, the caller reported a "man with a gun"...and it appears the dispatcher and responding LEOs didn't get further clarification, ie "is he pointing it at someone?" "does he live in the neighborhood?". Does he look familiar? Etc. the resulting LEO response was extreme, if the article is accurate, especially given that it was the dude's HOME.