I agree witrh BinMan62:
Economics 101 (a course failed or avoided by BA management):
1) Marginal cost to pax of free (bundled with fare) sandwich = unknown
2) Marginal utility of same = significant
3) Marginal cost to pax of BOB sandwich = €3 + lost goodwil toward BA
4) Marginal utility of same as perceived by former BA fan = under €3.
Of course this only matters if fare/schedule/route are comparable.