It’s not sneaky. They will have done it under the supervision of an ecologist. You have to have bar surveys during non roosting months and if bats are found, they have to be re-homed. They would then remove the roof and over hanging tiles to ensure the bats can’t return and will have to put to bat boxes on site etc. when the house is built they will have to have bat tiles etc etc.
bats hold up builds as they are highly protected so the owner will want to make sure that this is dealt with before the sale so that any purchaser has no problems going forward. It’s not sneaky. It’s standard.