There is nothing at all new in anything that the OP wrote except UA's desire to not permit online check in if the passenger checked a firearm on the first leg of the trip. Everything else takes place regularly at different airports.

dgk777's note is new - they zip tied the bag before they let you take it from the airport???!!! What was that supposed to accomplish, exactly?

I bet I know. After the idiot who took his properly checked bag to a restroom after retrieving it from the baggage delivery, then loaded it and shot some people, they must figure that you cannot open a zip tie because you can't possibly have an edged weapon on you so you have to leave the airport without being able to open the suitcase.

Inane to say the least but I understand the mentality.