I was just checking fares on UA's web site and saw a new fare basis I was not familiar with. So I checked the conditions. The last condition listed under section 1 was:
"TRAVEL NOT ELIGIBLE FOR MILEAGE PLUS ACCRUAL."
Needless to say I was very suprised. Imagine United selling fares not eligible for mileage accrual. This probably means no double miles either.
I think they may be trying to offset some of the miles they handing out at the moment.
FYI it was on their .de web site with fare basis VLGCDE and I was looking for FRA-ORD in NOV.