There are several instances in the past several years where Christian evangelical/Yidden for Yushka types have shown up in frum neighborhoods wearing Yeshivish/Chassidish lvush and engaging in low key missionary activity. The most gullible are recent BTs but others have fallen for this scam as well. There is a separate news story on YWN today providing more details on the Chicago case. Its totally legal from a civil law perspective but obviously poses real risks