Ayame's Scart states while this card is ready in your staging area, control values may not be reduced below their printed value.

Now I know it does not negates, but those it also keeps you from playing abillity that reduces control value?

no, you can still play the ability - in case you just wanted to draw a card from BRT.

all the scarf does is prevent the haxx without negating

Works very cheekily with Stained Honor for a (pretty much) free +5 to your next attack/action check.