well that number 17 looks suspicious to me…. Now I will check a couple of things.
(1) We call the WP oEmbed function as a matter of course. Normally in these circumstances, we would expect WP to perform the check on whether oEmbed is switched on or not and – if off – gracefully return having done nothing. I will check if this is indeed the case or if we should be checking that before we make the call. As I say if we have this wrong then this would be counter to expected behaviour.
(2) As I understood it (and this may have changed), the WP oEmbed function checked against a predetermined list of websites. This is the way it is defined in their documentation. But maybe they are in fact looking at each request regardless of the url. This would be a crazy thing to do but maybe… so I will check into this as well.