I don't have all the details but my bro tells me his daughter's family's trip SFO-Italy, France, currently taking place, was cancelled by her when UA upped $200
per pax allegedly for fuel surcharges, apparently after the original tix were issued.
Piqued, MA reticketed the whole 4 week trek on Delta, presumably without paying any fuel surcharges, though with a connecting flight out of DTW TATL.
Just food for thought...