I think the best chance of this working is mainly with people who travel for thier job,
As people rushing for planes seldom have time for anything. Hotel carparks frequently have some green / bush area's planting somthing there on a stopover would make it easy for a cachieralso on a stop, to find and transport out
e.g The Narita cache is a good example of how to move stuff around ,
yep a brill idea