@JTT,
There are still a few old diehards who know the difference based on ancient teachings.
For the most part, I think that nowadays we encounter whom/whomever when people are trying to sound fancy shmancy--and end up sounding wrong (to me and two other people out there somewhere).
It's similar to "between you and I." (Gag.) People say "I" because they think it makes them sound educated/fancy shmancy.
Back to funny signs for I.