That depends. Are your kids well-behaved, requiring little attention, or are they the types of kids who are constantly getting into things that they shouldn't, who stray too near busy roads, who don't return home at appointed times, who journey too far away, who can't be trusted near pools, who fight, spit, throw rocks, who break things and then lie about it, who tease, who steal, who bully, or who coax others into mischief?
If your answer is "no" to most of these questions, then have words with your mother. If the answer is "yes" to more than just a few of them, then listen to her.
"But my children deserve to play!" shouldn't be used as an excuse for bad parenting. I'm not accusing you of being a bad parent, but I don't know you, your kids, or your mother.