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Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 102,617
Not only is it rare, but you would still earn miles on the basis of the fare you paid. Moreover, there have been a few reports of GAs noticing that a Y fare basis on the upgrade list is incorrect and then un-doing the upgrade and returning the person to where they should be on the priority list for upgrades. YMMV.