[Terr_]

> This is just plain wrong. A WAF rule meant to prevent credit card numbers from being output would not block the server from accepting credit card numbers

Until you have any kind of JS code where the contents of an input box are round-tripped, so that the user enters a number and then either the interface brake so it starts getting blanked out against their will.

[bastawhiz]

That's literally just a variant of the issue being described here.