“(for example) “I need to secure my gun in my lock box, which requires I unholster it, and hold it in my hand while checking it for safety. I do not want to upset you while doing this. Also, I intend to do this in a safe manner, to avoid the chance of an accidental discharge.””
That kinda sounds like you intend to handle the gun and are just informing them, but that you are going to do it.
Always a bad idea to remove it from a holster if you arent asked. A VERY bad idea. Better just to ask. But i would very much avoid handling it without their explicit approval and instruction to do so.
Far better to just inform them that you are legally carrying, are no threat, and ask them what to do with it.
But clearing it, putting it a lockbox, etc, is too much fiddling with it if they don’t want you to. Especially if their intent was that it just remain holstered anyway.
Year before last I watched a Sheriff's deputy trying to collar a large mean dog. He got the stick collar on him but the dog had a brother that was coming to the rescue. The deputy looked straight at me and asked, "Do you have a gun on you?!?" I said yes. He said,"Good! If he comes at me again, put him down, will you?" I told him that I surely would.
As soon as the other dog saw me draw my sidearm he fled underneath the nearest house. Guess the dog's instincts kicked in and he knew I was about to kill him. He didn't come back out. All the deputy said when he left was, "Thank you sir."