Yeah, I imagine that is true. For our planted vivariums we only ever leave 3 types of animals in there (besides the mantis).
1. Springtails. Help keep mold down and makes cleaning minimal.
2. Isopods. Also help clean up the mantis waste. If you have a large colony, they work as supplemental food for the mantises. If you don't want them to become food, use a smaller variety.
3. House/Blue Bottle/Fruit flies, whichever is appropriate for the size of mantis.
We don't even feed roaches, worms, or crickets in the enclosure for fear that they will hide and potentially cause a problem in the next molt. I would put locusts in the same category. Not only will they damage plants, but they could become an issue if not eaten prior to the next molt. The bioactive setups are very fun, but the added complexity does make feeding a bit harder. Worth it IMO.