Grand jury is so named because traditionally it has greater number of jurors than trial jury, called a petit jury (from the French word petit meaning small).
Although mice tend to come out in the night when most of the occupants of the house are asleep or immobile. This allows them to stealthily infiltrate any of your food bags, crumbs etc. During the day time, mice will normally not come out, but if opportunities exist then they surely can.
Re: My cats are attacking my feet at night. I agree that shouting Ouch! and maybe shoving them off the bed is one way to go. Get it through their heads that pouncing on the blanket mice is not acceptable. One thing I will add: never, ever play the There's something under the blanket! game with them.