I would echo what was said earlier that every shliach is different, different things will irk different ones, due to the circumstances, or even just personality. They are humans too (gasp
).
The common point is that it feels to them as though people don't use their common sense, which I think is something we all relate to as being annoying.
That being said, different shluchim deal with it in different ways. Some will politely answer the questions and move on, while others that are feeling more overwhelmed might not have the emotional energy to roll with it as much.
Chabad of venice has an autorespond email with ALL tourist information when anyone just sends them any email