LogDevice is crash fault tolerant not byzantine fault tolerant if that's what you're asking. This fault tolerance is in regards to where the logs are placed not who's emitting them though. If you want to analyse logs for inconsistencies or attack patterns you should look into something like SEAMS/REAMS, it's completely out of scope for LogDevice.

LogDevice is payload-agnostic and doesn't inspect the value of the binary blobs it stores. If your writer is allowed to write according to ACLs, LogDevice will happily take writes from it regardless of their content (upto the max payload size). Verification of payload content should be done on a layer above LogDevice - either before taking the write or when reading.