As someone considering CloudFlare's SSL and CDN services, this worries me.
The bottom line is that this misfeature is an annoyance for 99.9% of internet users. Of those, maybe 1% understand how to get rid of it - probably by installing browser plugins that block the origin servers to some degree. I have no intention to use this (obnoxious) feature... so if there's any risk that part of my customer base will receive a degraded experience on my website, this is a compelling reason to use a competitor.
The internet has a way of "fixing" what it interprets as damage. For example, if I'm in a pool of shared IP addresses that gets used by spammers, I might find my legitimate outgoing emails blocked as spam.
Likewise, if end-users find that cloudflare provides irritating features on websites, they may very well develop browser plugins that block cloudflare services - even the 'good' services (deliberately or not). Maybe this is far fetched, but the bottom line is that anytime you associate yourself with unsavory activities, you risk getting hit by the blowback - even if you don't "opt-in" yourself.
Taking the long-term view, this cannot possibly be good for CDN customers who don't want to annoy their users.
The bottom line is that this misfeature is an annoyance for 99.9% of internet users. Of those, maybe 1% understand how to get rid of it - probably by installing browser plugins that block the origin servers to some degree. I have no intention to use this (obnoxious) feature... so if there's any risk that part of my customer base will receive a degraded experience on my website, this is a compelling reason to use a competitor.