For the record, I was being sarcastic and do not actually believe it was the customer's fault. I believe this is an abhorrent way of running business by Google.
Your argument appears to be this: "Facts are unimportant: the customer is almost certainly wrong in every case."
Assuming one knows about them. How would one learn about them, without making the same mistakes themselves?
> For example, if you're paying with card, have at least one extra as backup payment method (which most providers allow and recommend).
Please don't generalize. There are many countries where credit cards aren't common, and applying for just one (and getting it approved) can already involve a lot of work and take lots of time. Such as: the bank and the national credit authority needing to do a thorough credit check, you having to supply proof of identity and stable income, the bank having to register your new line of credit with the national credit authority, etcetera. Applying for multiple CC's, if at all possoble, only adds more trouble: your registered total amount of credit will rise (even if you haven't used any of it yet) which can limit your options for any other loans like a mortgage, a car loan, a subscription, and so on.
When the due invoice represents less than 5% of your lifetime value, the least they can do is eat the cost and wait for you to resolve the payment, because, at worst, they’ll lose 5%.