I doubt it. Chances are, the average tutored student will be from a better off socio-economic background, while their parents place particular emphasis on education. Chances are, the tutored student will perform better than the "average" student.
Whether tutoring is successful will still depend on the effort/talent combination. Like a normal teacher, the concepts conveyed by the tutor must be understood, and work must be done to actually "learn" from him/her.
I don't think it will destroy anyone's credibility - maybe to those who share your elitist outlook, but to the rest of us, you will just look like a elitist (in the pejorative sense).
The decreasing importance of correct spelling and proper grammar reflects the evolution of the medium. Let's face it - when your reading a novel or a traditional print-based text, it's gonna have gone through numerous editing stages. Likewise, shorter, informal texts such as letters, internet...
I did alrite but I found it pretty hard. Hopefully 75+ if stupid mistakes are kept to a minimum.
And wth Adam got under 80?? are you serious??
Ah well there goes our chances of getting a 100 uai :(:(