DY, I have done, though I am working for a great Jewish organization that is not directly in the kiruv field at the moment.
In most cases, I would not turn it down. As I indicated above, I do not put myself, my community, my employer(s) or my ideals on a pedestal, and proclaim them to be the standard by which others should measure if they want to be considered “frum” “heilige” “erliche” Jews. So without that baggage, I can make a nuanced determination, with the input of the halachic authority of the organization, with my conscience, with the standards set by the board of directors of the org, and with the law of the land. Because I am not trumpeting my actions as the gold standard (or indeed the standard for anyone other than myself) I won’t suffer from that aroma of hypocrisy that is so hard to avoid once one has stepped in it.