So I am waiting for my delayed (2.5 hours) flight to board at DTW when I am summoned to the podium to show my passport.
I am told I need a visa since I am flying into MXP and out of LHR 100 days later (more than 90 days). I had to show my EasyJet ticket from MXP to LHR for 3 August to get a visa override.
It may be that the days of one-way and open-return tickets are over, or was this event just a hiccup?