Any reason not to place stand mounted speakers upside down?

I ask because, for example, Harbeth perform best when the tweeters are at ear level, but I have some very good stands (Osiris!) that are taller than ideal. So, if I were to place them upside down...

Apparently Alan Shaw sees no problem, but points out that the bass would be boosted. I'd be interested to hear other views.

Cheers,

Tony