I have mead that is 9 years old, with plain Brewer's Best beer caps. I've never bought those o2 absorbing caps.
I've never tasted beer or mead that was oxidized either. I suspect they are another invention to solve a problem that doesn't really exist for 99.5% of home brewers.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10