1) I see no reason to put them into character meals.
2) The character meals get filled-up with the need for them.
3) They could be disturbing in a meal as kids might get up and chase after them.
4) In addition, kids might want to take longer with them than other characters, causing delays.
5) Kids might also want to wait for them, to come around again.
. . . this would cause people to stay at their table longer
. . . this would reduce "table turns"
. . . this would reduce Server tips and restaurant revenue