There are events that require certain attributes, for example in their description, that are not validated using the validate_data() function. An example of this in core is the event 'cohort_member_added', where the 'relateduserid' is used in the description, but isn't necessarily set by the event. We should be validating 'other' fields as well if they are used.

Note: There is no need to validate the 'objectid', as this is done in the base class when the 'objecttable' is set (just pointing this out as I have seen this validated in some core events).