This is very irresponsible. You should never let loose any unwanted or extra roaches to the environment. Even if they're native species there's always the possibility of introducing a disease that could affect them or other species. This applies to all pets of any kind. If you need to dispose of extra roaches then you should double bag them, put them in the freezer for a couples days, and then put the bag in the trash. Look at the problems Florida is dealing with all the non-native animals in the everglades and elsewhere that were once formally kept as pets.