[xyzzy_plugh]

If you can convince VLC to render the subtitles into a new video stream then it'll work. You're effectively creating a new video though. By default VLC just renders subtitles in the player, you need to encode/transcode them into the output stream.

[Scoundreller]

I’ve “burned” them in with handbrake before. Took a while but it works.

[freedomben]

I burn subtitles in routinely with ffmpeg. Not a light operation, but it is highly effective at making sure they work at watch time