“She tells me to punch in my telephone number (I use someone else’s) and magically 30 plus percent is saved just like that. ”
Perhaps that is a marketing ploy that is peculiar to USA?
I have never experienced this before in UK or any country I have travelled in.
In UK, we have store cards, which offer discounts. I have a few for the stores I shop in regularly - it’s so long since I applied for them, I can’t recall the info asked for - I think they wanted an email address but that is no problem for me - I always have a disposable “junk email” address ready to give for any retail or online purchases if needed. I never give them my main one.
Most folk I know do the same - I find that folk in UK are generally more savvy about marketing ploys nowadays.