5e is not 3e, and any conclusions drawn based on comparisons to 3e (or any other previous edition) are prone to error.Well, in 3e, there was a spell called dimensional anchor which prevented such spells. Given they removed that spell from the game, I assumed it was possible to do without needing an actual magic item. Especially given the fact that 5e doesn’t rely on PCs needing magic items at all.
Can't you just gag him? Or is he using Subtle spell?
I didn’t really compare. I assumed the two editions worked differently.5e is not 3e, and any conclusions drawn based on comparisons to 3e (or any other previous edition) are prone to error.
My assumption, when they put details like that, it is to illustrate the limitations of the spell. To me the ‘you can - but only to this limit-’ indicated a limitation of being able to carry no more than your carrying capacity which prevents people from using the spell to transport two ton rocks or vast amounts of treasure. Others interpret the ‘you can’ meaning “you don’t HAVE TO’ which allows you to wiggle out of things like manacles. Both legit interpretations.There is, in fact, a Sage Advice about this:
Seeing as how you wearing the manacles, they go with you.
I don’t see any reason you shouldn’t be able to dimension door away from a cursed item either, unless the effects of the curse include not being able to unequip the item.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.