1. A computer-implemented method comprising: receiving information about a proposed outgoing message stored in memory, the received information comprising text content of a body portion of the proposed outgoing message and metadata of the proposed outgoing message; using a first classifier to classify the proposed outgoing message into one of a plurality of specified classes, to obtain an expected class of the proposed outgoing message based on the metadata of the proposed outgoing message and not the text content of the body portion of the proposed outgoing message, the first classifier being a multi-way classifier comprising N*(N-1)/2 sub-classifiers where N is the number of the plurality of specified classes and each sub-classifier provides a one-to-one classification determination between two specified classes, the metadata comprising one or more of: information on whether the proposed outgoing message is part of an email thread; information associated with a file attached to the proposed outgoing message; information in a subject line of the proposed outgoing message; information on voting buttons associated with the proposed outgoing message; and information on one or more required receipts associated with the proposed outgoing message; using a second classifier different from the first classifier to obtain an actual class of the proposed outgoing message based on the text content of the body portion of the proposed outgoing message and not the metadata of the proposed outgoing message; comparing the expected class of the proposed outgoing message based on the metadata and the actual class of the proposed outgoing message based on the text content of the body portion; and triggering an alert in response to the comparison failing to yield a match.