When the ignore_public_acls attribute in the aws_s3_bucket_public_access_block resource is set to false, S3 buckets may still honor any public access permissions granted by existing or future bucket or object ACLs. This creates a risk of sensitive data being inadvertently exposed to the public internet if a user or process applies a permissive ACL. To prevent this, ignore_public_acls should be set to true, which ensures that all public ACLs are ignored and cannot be used to grant public access.