Plugin: modules or generators?


I’m writing a plugin (my first) that adds question validation support
(alternative to captchas).

I’m obviously gonna need to provide a generator for the migration of the
questions table, I’m just not sure if I should generate the model too or
just leave it in the plugin. If I do leave the model in the plugin then
won’t I also have to hardcode to table name in the migration? If I’m
generating the model, should I just generate the lib/ system file too?

Also, is it OK to add an error to a record if the table doesn’t actually
have a column for the error I’m adding?