Becks - don't pluck my eyebrows [honest!] but when I yank the odd nostril hair out, or tiny ones just under my nose that I miss when shaving, it always makes my eyes water, then I usually sneeze afterwards. The nerves must all be connected somehow. ;+))
Interesting question, one of things I wondered myself but thought it just happened to me. From what I have found out, eyebrow plucking excites a branch of the nerve that supplies your nasal passages. Nice!