narvik

United: sometimes the UA employees seem to be completely "self-employed", i.e. they do things by themselves [in what appears to be] in complete autonomy from United. Have a feeling that something similar happened in this case.
Although there seem to be some inconsistencies, a vagueness, and usage of incorrect terminology ("carry-on" vs. "personal items") in the OP and subsequent posts, it's not inconceivable that OP was COMPLETELY in the right with quantity and sizes of their luggage, but the UA agent/gate agent saw them approach the desk with what appeared to be a heck-of-a-lot of items/bags/stoller/pack'n'play/chillybin/backpack/diaper bag, so they immediately went into their:
"Hang on a second. No way I am allowing these guys to get on my plane with all of that crap!" mode.

FastFood/McDonalds: I think the UA agent/GA in this case has the EXACT opposite attitude from this guy:

AugustusM

That was the first time I ever had an issue with that bag, I purposefully use it because it's about 2/3's the size of the limit and easily fits in the sizer along with my laptop bag.

keisari

QBK
I like your approach
It is not emotional but contract related
My brother always tells me "it is not personal" but it is very hard to calm down enough to take away the emotion
I find that when I write the letter/comment, even days later, my brain re-lives the emotion I felt at the time
So many times, when I am wronged (by hotel, lounge, airline, etc.......) I just move on instead of re-living the entire disappointment.
Your advice, though, is excellent

notquiteaff

I don’t know what the size of the OP’s P&P thing is, but the agent didn’t apparently insist on it specifically getting checked. In other words, it wasn’t an argument over the P&P item exceeding carry-on size. If I had to guess, they just looked at the pile of stuff and determined (without actually counting, and perhaps forgetting the baby had a paid seat) that it was too much.

Let’s look, yes. Where does United document the maximum weight for carry on items?

CRJ uses green tag valet cart for carry-ons that don’t fit into the tiny bins, right? They didn’t let you put your one properly sized carry on bag on the valet cart? What was the reason they gave you?

SS255

For a moment there, I was expecting you to say “Cholula sauce.”

AugustusM

It was green tagged, the reason they gave was that it looked too big and they wouldn't let me size it. I know it 100% will fit along with my laptop bag because I've done it before in CVG and LAR.

It really was a debacle but I wasn't in the mood to argue with some outstation nudnik and instead called the GS line when I landed. They gave me compensation and said they would reach out to the station manager so they could train the person in question.

notquiteaff

So it was really a completely different scenario that the OPs.

COSPILOT

There is something strange about flying with kids that seems to create havoc where none is needed. I'm convinced agents are so focused on Dad carrying multiple pieces of carry on luggage while my wife keeps the kids in check that the quantity per person is often not realized. All they see is that I'm managing 6 items, despite the fact I'm doing it for four people with four seats. Not an issue now as my kids are 14 and 11, but when they were very young and we traveled, I would often have a way of creating a train with carry on items (all within sizing limits). Apparently 1K's don't have families in the eyes of agents, but that shouldn't matter in my case, or the op's case. If its within regulation and quantity, getting beyond check in is none of their business.

Actually the above isn't unique to agents, but also fellow elites when I'm boarding. The thought that I'm a 1K doesn't enter one's mind, just that here is a family with a ton of crap, cause Dad looks overloaded, stressed and sweating. Mom looks the same of course. Point is this is all someone sees, completely forgetting policy, status, or anything else. I did enjoy when we would board our flights with young kids and the horribly disgruntled looks would come from others in First Class, only to realize my kids were perfect angles on the flight. That was always priceless as more than once others would compliment the kids upon arrival of how well behaved they were.

spartacusmcfly

A picture of the items and a poll asking 'ok' or 'not ok' would have addressed this topic far more efficiently

PDXpress

For a good time point out that diaper bags don't count against carry on allowance and be ready to say "how dare you embarrass my 10 year old by asking why s/he needs it."

ContinentalFan

When I’ve been asked to gate check a bag (not check in) I insist on declaring extra value. I don’t take “no time” as an excuse. With one exception, it’s catalyzed the successful search for space and the bag has come with me. The bluff failed once, so I had to pay $50 or $100 to transport laundry.

Cholula

A person of good taste IMO.

canadiancow

There were three passengers with three seats. Only one of the items had to be a personal item.

SAPriorityTag

Bravo! Thank you! Overhead bin space issues on the CRJ would not be the same as the 73G!

AugustusM

He was forced to gate check a bag at PSP which it appears that it was not required to be gate checked. Same thing.