I'll also point out that such items with continuous effects are truly continuous. There is no off switch. It's always on and can never be shut off until disenchanted/destroyed.
I was involved in a forum discussion about continuous effects a while back, and continuous effects on items are kind of a mess, in that they don't work that people think they should work, or it is at least not intuitive...
Here's the discussion: Permanent Control / Enchantment