It depends on the type of Wormery you have. From a home-made or poorly made Wormery escapees are likely. Our Original Wormery has been designed to keep worms in as it is a fully sealed unit, but it is possible you might have some escapees.
Escapees are especially normal with our Tiger Wormeries and it's likely you'll find worms in the sump tray, up the sides of the trays and the lid. You can just put them back up into the working tray and eventually, they'll settle into their environment as long as the conditions are right.