In most Jewish communities, those who are honored with leading the congregation in prayer, or those who perform a public religious function such as receiving an aliyah or lifting the Torah, don a tallit. This is considered to be respectful of the congregation. This custom applies to: a) Unmarried men, who according to Ashkenazi tradition do not wear a tallit. b) The afternoon and evening prayers, when even married men do not wear a tallit. c) A person not participating in the prayer services who receives an honor.
In many other communities — Chabad included — this custom was never adopted. Thus, in these communities not wearing a tallit obviously isn’t considered a disrespect for the congregation.
If praying in a synagogue whose custom is different than your own, you may follow your own custom, provided that it won’t cause any friction or quarrels. The exception to this rule is wearing a tallit during evening services, for those who traditionally do not do so. According to kabbalah wearing a tallit at night can have negative consequences, and should be avoided if at all possible. In such an instance, politely declining the honor of leading the services is probably advisable.