So, I'd like to anchor an increased reflexes sustained spell to my belt buckle (or whatever). I cast the spell, pay the karma, etc. But I need to pass through a ward. So I turn off the anchor. When I turn it back on, is the spell still there and functional?

AFAIK, anchoring does not provide an on/off switch. All it does is put the spell on 'hold' until the triggering condition takes effect.

An anchoring focus just increases the versatility somewhat, allowing the 'held' spell to be 'given' to mundanes/moved (rather than the caster/fixed point).

If you want an on/off switch, you have to use a sustaining focus. Bump into that ward, switch off the focus , walk through ward (or have ward deactivate focus trying to get through said ward), recast spell and reactivate sustaining focus. Time consuming and annoying, but magic is not all roses.

Yeah, the "Bullet Magnet" part of being a magician really sucks badly.

Especially if you're just the guy that's doing illusions for children's parties!