More importantly, and it covers both spelling and grammar, we have lots of folks for whom English is a second language. As long as they can manage to express things clearly enough that we can winkle out the meaning, I'd rather not drive out their input for SpellingCop(TM) reasons.
After all, Ye Olde Tongue ain't what she used ta' be, no half! English has changed a lot (including spellings) over the years and it will again. Maybe some of the folks with poor spelling really are just avante-garde. I mean, OED is now starting to include words like "wedgie" and a lot of linguists are defending netspeak (d00dz, WTF U ROFL about?, etc.) as being fresh and bringing something back to language that has been missing since we did much of the codification in the last couple or three centuries.
Now, one last point, we're pretty far OT (when getting into spelling, etc) on a thread talking about Subsector UWPs... (I think I am certain this violates at least one forum ettiquette proscription)...