Some say that people who has BO are the ones who doesnt know that they smelled. (I dont know if it is a joke or truth)

I feel your pain.... sitting beside someone with BO is nauseating.... its a daily battle for me with taxi drivers and colleagues.

But if i am going to fly, just like nomad, i bring vicks vaporub with me.

so my answer to your question is NO, i dont think that they should be denied of service.