Eureka! I have discovered the cloak of invisibility!

Yes. I've walked out of car showrooms before now when I'd gone in to buy a car for myself.
It's not just us older women though. DD is a glamorous blonde and had gone in to a showroom to buy herself a posh car (well it is to me!). The salesman spoke only to her DH. Unbeknown to the salesman, you don't mess with DD. He wasn't to know that she'd contact the owner of the whole dealership about 'Sid the sexist'. She got a huge discount and apology and the staff got extra training on valuing female customers.

The only time that happened to me was when I was considerably younger and looking to buy a car. The salesman only spoke to my husband and incensed me so much with his attitude that I've never been back to that particular garage. I haven't experienced it since or elsewhere

I have a similar experience to friendlygingercat. Though this was a queue in A&E to see the receptionist after booking in for my DH. Was called and just about to move towards the only receptionist on that day when a man seated by the desk suddenly jumped up and went to the receptionist practically knocking me over and started asking her about his wife who had gone for an x ray, how long would she be? Where was the X-ray dept etc., and when the receptionist answered him which I was cross about because they are usually trained to cut people off mid sentence, the man started joking/flirting with her. Finally, when he had finished I moved forwards again but suddenly he jumped up again and was making a bee line for the receptionist, however, this time I strode in front of him and said loudly to the receptionist “maybe you should have another member of staff available for chit chat with queue jumpers”
And a couple of people waiting behind me issued words of support.
A&E really isn’t the place to do this, there can be blood on the floor and it isn’t from an accident if a person tries to gain an advantage.

Something similar happened to me in a computer shop some years ago. As everyone knows women know nothing about computers! (I have 2 postgrad degrees in computer based subjects).

I was with a relative and a man who entered after us managed to grab the assistant first, even though it was obvious we were there first. They were discussing his possible purchase of a printer. Nevertheless we waited patiently for their conversation to finish, and the assistant was free. He was in process of dealing with me when customer re-entered the shop and immediately began to speak to the assitant as though I was invisible. He evidently thought it was accetable to leave and then return as if nothing had happened in the meantime.

I immediately used my rather terse "teacher" voice to direct the queue jumper to the fact that the assistant was dealing with me, so he would have to wait his turn. "But I was here a few minutes ago ...." "And I was here before you and you queue jumped ahead of me then. You lost your place in the queue when you left and your not doing it again." I took a big roll of notes out of my pocket, and asked the assistant did he want a cash sale as we were happy to go elsewhere.

The assistant apologised to the queue jumper but continued to serve me. My relative often reminds me of the expression on the queue jumpers face.

Ive put pushy males in their place on numerous occasions and always enjoyed the power rush. However I am tall and imposing for a woman and that does help.

Aely I love it. So many times I’ve felt invisible. Now I know what to do thanks to you.

Similar thing in PC World, the man immediately started speaking to my husband who, instead of redirecting him to me who knew what she was talking about, told him what we wanted but was unable to carry the conversation forward as he had no real idea. The man however carried on trying so I went for a walk round. Eventually I bought what we needed and went back to OH and said are you ready to go, the man looked so relieved.
PS, why did 'my husband ' auto correct to 'nightstand '?

Likewise at the Globe, I was waiting to be served at the bar when a man (of course!) behind me reached over me and picked up his drinks which he had ordered over my head.
I may only be 5’2” but I was close to jumping up and down and shouting “Me, me, me first”

The same thing happened to me in a car sales room.
Apparently women don't buy cars and never go into these places without a male companion! I was invisible and the salesman was greeting the men who came in after me, asking how he could help but ignoring me. I did ask him if I was invisible - obviously I was because he looked quite startled.

He then said he assumed I was with one of the gentlemen - why?
I did buy a car there but not from the salesman who dismissed me twice.

It went back the other week for its service and the same salesman rushed to make me a coffee. He didn't remember me, I don't think, but he obviously learned a lesson the year before.