Ethics of soliciting letters for US permanent residency application? I recently received a request from a postdoctoral associate working at another institution to "write a support letter" for his residency application. I put the statement in quotes because the candidate in question has already written out the letter and is asking me only to put it on official letterhead, sign it, and return it. 

Is such behavior considered acceptable for the US permanent residency application? Is there a difference in appropriateness if the applicant knows the recommender well?
For me, the key criterion is "do I know the person through shared endeavor" e.g. having studied or worked together for a reasonable period of time.   

If there has been no previous contact i.e. a stranger, I would NOT respond at all to a request for a support letter.

As a possible comparison, a stranger asks you to guarantee a bank loan for them ...  most people can see where that one will lead...