Great analogy! Despite enjoying a long relationship, Paypal will very possibly stab you in the back and rob you blind in a blink of an eye then become incommunicado.
"Oh, yeah, don't worry, 3D secure can't be forced for all payments, but we got you, we'll enable it when we think it might be abuse. Also, our seller protection covers you."
All the time: "Here is a customer that made 12 purchases during the last 13 months. We took the money, but you have to prove that the card wasn't stolen and that the customer got what he paid for. We didn't enable 3D secure for this transaction, so please fix this for us and we'll give you your money back. Also, if you don't we'll take some more money from your account. Seller protection does not cover this as services are in a gray-zone."
240K frozen and taken since 2012 and still counting! At least I've started to win all the cases, but it takes a lot of time. Time to switch to stripe where I can force 3D secure...
It's like living with a drug addict. They may be family but you sure as hell dont leave cash or valuables laying about...