[criddell]

He addresses this:

> The one downside is that occasionally you’ll get a creator who disabled playback for YouTube embeds. This is rare, especially with videos made in the last few years, but for those Juno will auto-detect that and just load up the normal video website page rather than the fancy player.

[Aissen]

That answers my question about the embeds not playing at all (thank you, that's what I get for speed reading), but I'm curious if there are other limitations.