You're right that credit cards are far from guarantees. Still, I'd imagine Cloudflare do something like cluster users by risk level at some granularity. Brand-n

You're right that credit cards are far from guarantees. Still, I'd imagine Cloudflare do something like cluster users by risk level at some granularity. Brand-new paying accounts might be put together in the same process, while paying customers for over a year might be in another. You might be attacked even in the latter group, but the attacker can do that at a much lower frequency (the card isn't recently stolen; and they've been paying for this attack for a year - only to be kicked out now if found). Also, the browser risk model is much worse because of the scale. If you manage to get malicious code onto a popular website then you get many, many opportunities to attack people. With Cloudflare you can only attack the other tenants of your process, and you're paying every time you do it (in a browser, it runs on the target's machine, free for you). And even then as the blogpost mentions they randomize pairings, limit the amount of time they spend together, etc. Overall I think this is far less risky than the browser situation. And Cloudflare isn't the only one that thinks so - their competitors also put multiple tenants in the same process. Done carefully, it's a reasonable model.