There is now a bounty of 350 points on "By foot" vs. "on foot", the endless stream of low quality answers from anonymous and unregistered users was depressing. The question has attracted 42k views since it was posted, it seems there is an effective need for a concise but comprehensive answer.
Let's hope the question attracts some high-quality answers and up-votes which will indicate the community's general consensus.
I see that the accepted answer is regaining upvotes. There are a total of 13 upvotes against eight downvotes. May I point out, (which Rathony also picked up on) the user, snumpy, says, and I quote [emphasis mine]:
When it comes to using "on foot" or "by foot," either would be correct; however, a quick google search demonstrated that "by foot" is more commonly used (150M hits vs. 85.4M hits)
Evidently, the above affirmation is false, none of the answers posted since November 26 have confirmed this bold statement. Therefore, the above answer is inaccurate and extremely misleading. Despite Tim Lemington's affirmation
… over time, the better answers will get upvotes, the bad ones will not.
it appears that the community continues to upvote poor answers.