You guys are either in high risk/high security occupations or have been watching too many spy/crime movies. Do you really think someone out there will study your travel patterns and set up an ambush. Maybe a crazed anti-bike sniper?

My argument about sharing routes is that there are so few people riding with similar start and end points. I ride to work via one of 3-4 routes (with some variation, depending on traffic or construction) However I come home by a vastly larger selection of routes, some as long as 40 miles for my 8 mile commute.

BTW- the bicycle route feature on Google routes is pretty good. I entered start and ends on many of my typical rides, and Google often has what I've already found to be the best route. They also allow folks to input corrections and suggestions, directing people away from busy roads or those with lousy pavement or lane width. This feedback loop, if used enough, and make this a great tool for newbies, giving the benefit of the experience of knowledgeable locals.