Make a Noise
One of the best pieces of advice I would give to new parents, “hide and seek” has an additional rule.
If the seeker says, “make a noise” the hider has to “Beep”
The kids have more fun, because then they can actually find you.
They will also believe that this is how hide and seek is played. You will be able to find your kids in the future, even when you are not playing hide and seek.