Making up numbers (99.9999...%) as hyperbole is considered rude here.

If you say so. Lucky for me I am conversing with someone more rational than most who isn't likely to be tripped up by my accidental rudeness, especially when he can see what I meant anyway. But good to know as I certainly lose more of the audience than I'd like in most of my posts, and I will benefit from creating a list of trigger phrases to avoid.