I guess I'd rather not offer such a deal to a "stranger", as I reserve the right to change my travel plans (both outbound and date of return flight) quite whimsically on very short notice - including simplifying routes to avoid primitive, uncivilized FRA.

Plus, I'd expect that my companion might need some flexibility, as well. Plans can change, and such changes can be costly and/or inconvenient for the accompanying party. If you need a reminder, just remember the ungraceful fate of berlinflyer's "painful self-experiment".