Ok, ok. Let me put it this way. For most examples where "whom" is used you can simply replace the word "who" where it sounds natural. I now realize prepositional phrases are a different story. Let's examine your example "By Whom will this tasty burrito be eaten?" I admit it's not a matter of a simple replace, but that's the thing. The entire sentence is formal and elitist-sounding. Most people would say "Who will this tasty burrito be eaten by?" Oh no, it ends in a preposition. Run for the hills! Edit: I had claimed my burrito example to be correct usage of "who" but it seems to be incorrect. That's exactly why I usually don't worry about it, and use "who" all the time.
Yeah- it is. I saw 2 of the guys from Mettalica at my favorite beach bar in Margarita Island on Christmas day 2000. I didnt talk to them other than- to say Merry Christmas. Really chill spot and it would have been so un-cool to bother them.
Just use who all the time in order to keep from looking like a tool Saying who instead of whom every once in a while is easily forgivable by 96% of the population. Saying whom instead of who makes you look like a jackass. Unless you really want to get into the details it's just easier that way. If not then whom is used anytime it's the object of the sentence (direct, indirect, or object of a preposition) Who is used when it's the subject of the sentence of the predicate noun. However whenever there is a whole clause that is a direct object and contains who/whom you use who if it is the subject of the clause. ie: I know who jumped on Mary's back. See it's just easier to use who all the time.
People used to bust Winston Churchill's balls about ending a sentence with a preposition. His response: "This prescriptivist grammar is something up with which I will not put!"