This post just proves nearly no one understands how their clutch works in their car. The bearing is always under spring pressure against the clutch fingers on all Mustangs since 2005. There is a spring in the slave cylinder which forces the throwout bearing against the clutch fingers all the time. Now resting your foot on it would add pressure to the spring and yes that could make it wear faster so keep your foot off. But the bearing is always turning whether foot is on it or not.
If the clutch is not slipping it is not wearing.
2010 GTRR in 5.0 Magazine [http://www.mustangandfords.com/featured-vehicles/m5lp-1212-2010-ford-mustang-gt-rr-total-fabrication/viewall.html]
2015 White SC, PP, etc....