I assume that's meant at me and I have to ask: Why is it wrong to spit around other people/public places/in apartments or houses? Why?
Because of 'peer pressure' AKA society doesn't appreciate it, right?
(What animal mother has a problem with their babies spitting, hmm?)
It's not about humiliation, it's about SHOWING her (when reasoning won't work) that other people DON'T like it.
If, however, a child is super-sensitive, then care should be taken and humiliation ought to be avoided, if possible. Then a professional might need to be consulted.
I still don't see any humiliation in having a child clean up his own messes, when he is CAPABLE of doing so (my 3-year-old can wipe up his own spit if I just provide him with the tissue).
Today, my 4 year old daughter 'took a drink of water', then SPAT it on the floor (at least twice that I'm aware of). I turned to her when I caught the second incident and told her STRAIGHT out that SHE would now have to clean it up and explained to her what to use and where to put it afterwards - she was, actually, very proud to do the job (I hadn't expected this) and promised she would NOT do it again (I believe she MEANT it, but.... we'll see). Then, my son wanted to clean up too (I'm NOT at all for child-workers, but the kitchen floor was wiped 'clean' with papertowels! - A bit of an exaggeration since they weren't wet nor was there any soap of any kind, but... it was cute, nonetheless, how they were totally proud of themselves afterwards).
Just mean, I went through this... sorta... it was water, not saliva.. but....
Or.... maybe I'm wrong and should just keep my mouth.... hands? shut?