This, I suppose, has little/nothing to do with PlayOn/PlayLater & I don't really consider it an 'issue' that MediaMall needs to address. Just posting since I didn't see another like it.
I'm aware that Hulu supports closed captioning and can be enabled by default [where possible] via their website. (win!) This works fine so that's not the issue.
However, although Netflix also supports closed captioning, it cannot be enabled by default [where possible]. When playing a movie or tv show that has captions/subtitles, it must be manually engaged.