In the alerts you can send the tags but only if you define it directly in a monitor (user defined tags) but you cannot send the tags of the parent monitor group to which the monitor belongs (Monitor Group Tags).
This functionality is interesting if you have many monitors or you add new ones within a group of monitors, so that they inherit from the parent.
You could allow to overwrite the value of an inherited tag or add a new one (as it is done now) and send it as well.
I attach an image.
Thank you very much.