Stage Monitoring - In ear vs wedge

[webephishin]

Has anyone ever come across any literature that they care to share as to why Phish doesn't use in ear monitors?  I've never used professional ones (my band has tried with over ear headphones in a small practice space but the bleed from the drums/bass is too great to be effective), but I feel like I would play better with wedges as long as the mix is good.

[Arafel]

This talks about their monitor system in 2009, but doesn't say anything except they like to go old school:

http://www.mixonline.com/news/tours/phish-tour-profile/368165

I will say in ears are awesome for singing, and I like the hearing protection they offer when they are run well.