satanika said:
Well it is still up to the players software/firmware to honor the 'forced' flag I think, similar to region codes etc.

Another option might be in the players settings where you can often set the default subtitle language and whether it is on or off by default.

That's not the problem. If I pop in one of the old german Kinowelt DVD releases I get the forced german subs while watching original english language all the time and I can't deactivate the subs. Neither the Xbox 360 nor the HD-EP10 can deactivate the user prohibitions. I think the real forced subs work differently than the muxman/ifoedit setting.