In several versions/builds of BS.Player there has been (and IMHO still is
though I didn't test it very recently) a problem concerning the switching off of (trying to) download of on-line subtitles, which didn't/doesn't work
exactly as promised by BS.Player-team.
Unfortunately you do not mention which version/build you're using.
However, if you don't ever need subtitles as mentioned by you, perhaps the most reliable method (also for older versions/builds) is to set movietime at its max as follows:
(rightclick >) Options > Preferences > Subtitles > [Online subtites]
Now set the value in the box "Download only if movie is longer than (min)" to 360 (which is the maximum accepted by BS.Player).
In future, unless your movie exceeds 3 hours playtime, BS.Player will not try to download on-line subs anymore.