First: Do you talk about AcoustID? There is no such thing like AcousticID.
Then: Someone has to initially send such an AcoustID (or more exactly: a fingerprint) for a specific song with some metadata to the AcoustID-Server. From this moment, many other users can make a lookup with the same AcoustID and get back the previously submitted metadata.
If someone would transmit WRONG metadata for a song, it could happen that you get this wrong data back for your song. There are several threads how you can fix such situations.