I just realized that when I post this link with the intention to have it oneboxed:
it is rendered as an ordinary link because the website obviously doesn’t support OpenGraph. In cases where that happens, I tend to change the text so that the link becomes an inline link. And in that case it renders as a mini-onebox: Public Register - Current list of services declared under the CISPE Code Of Conduct Nice!
So I’m wondering: wouldn’t it make sense if the ordinary onebox would fall back on mini-onebox whenever no meta-data is available?