there should be the ability to select photos and delete them from the albums, or even when it asks for tagging. In Picasa Web Albums, the options show possible matches and there are other choices where it says "not a face, skip, ignore etc..." there should also be a "delete" option that allows us to delete "this picture" or "delete all pictures with this person" and all these can be incorporated in myheritage photo section too.
I recently imported pictures from facebook and picasa. both times, accidently imported all albums. now there are people from work and school who are not related to me. when go to the tagging option, those faces keep showing up as well. the delete option will take care of that.
right now I am marking them as "Person X" and then deleting them there.