Best not to overthink it - The sales clerk is trained to ask for this stuff.

Luckily most times I encounter this I just tell them no I don't have a phone number with them & continue checkout like normal. Sometimes that means not getting a sale price on something but usually I avoid those type of member-specific sales anyway.

And worst case - Just make something up. At Best Buy a sales rep absolutely refused to sell me something from the mobile dept without my info. Which didn't make sense because earlier I had bought something at that same Best Buy with a different rep & that rep took my order without my info no problem (she said she had to enter a phone number but just entered Best Buy's).

Yet this particular sales rep refused to proceed without info, so yeah he got an entire fictional name/address/phone/email on the spot.

I realized a few years ago that my GF inadvertently solved this issue for me: She likes registering for anything that provides a discount, so I use her phone number.

"Are you a member?"
"Nope, but my GF probably is..", and 90% of the time I am correct.

Here it's similar. I've found out that if to the question

do you have our membership?

I respond "No, thank you", they often understand correctly and don't assume I want to set one up

A long time ago they wanted a phone number for me to get a hair cut. She looked at me like I was crazy when I said no.

(Your Area Code) 867-5309. None of the younger store clerks know the song reference when I give them this number. But I get chuckles from older folks in line behind me

From a privacy point of view, it makes pefect sense to not share your phone number with a merchant. The only buisness you have with them is a single transaction, they don't need any more information about you other than knowing that you paid.

I asked nicely why do I need to give my phone number and I was told that to register me as a member so I can get the discount.

I declined and said I don’t want to join and would like to just pay.

I've just said "I don't have one" when asked this for awhile. This never seems the phase the cashiers, I'm guessing they know what that really means. Half the time I still get whatever discount, though I've never tried to sign up for a membership saying that.

If it's an online form my phone number is just (local area code)555–5555. I've never had that not take, except for one case where it automatically enabled 2-factor auth and I had to create a new account.

I had this experience once in an Ikea, of all places. I calmly told the clerk that according to local laws (which I cited), it was illegal for them to demand that information from me (phone number and post code) to sell me anything, and if the computer wouldn’t let them do it, then they should call a manager for an override.

When the manager came, the clerk said “this person refuses to give me their info” — to which I added, “your computer refuses to comply with the law; please override and then notify HQ that they are in contravention of the law and liable for significant fines.”

The next time I went in, they still asked me for the info, but the clerk was able to override. I suspect they just put in fake info for everyone who refused to supply it.

Maybe just an awkward sales agent, or they thought you were mad at them for in their mind trying to help. I decline phone number and zip code all the time. Also been using someone else's phone number at grocery stores for years -- started by mistake. I don't care about accumulated points or whatever but discounts at grocery store are pretty significant for me.

But I understand your frustration in general. Keep up the good fight :)

I was looking at ISPs yesterday as my current contract ran out so they're taking the opportunity to wring me for all my money. One place I looked at has a regular price and "members price" for every plan. I go to see what a membership entails and it points me to download an app. No clue if the membership is free or not because I don't want or need an app for every utility and purchase I make. People like you and I are not the norm but from my viewpoint you're being reasonable and the world has lost all sense of normalcy and reason.