Thanks for your inquiry. I would first suggest that you find yourself another immigration attorney. You never want to provide a negative response to any question asked on any form which you file for an immigration benefit with the reasoning for that response is that the government should know about it so you do not need to tell them. So instead of wasting your time with someone who does not understand the possible negative implications that can arise depending on how responses to questions are answered on immigration forms, find yourself someone with a little better of an understanding about the concerns that you have with your case.
Now with that said, the truth is that the response is unlikely to make the application go one way or the other, but you never want to leave that possibility as an open question. If you are unsure as to how to respond to a question provide the response that you believe is best AND provide an explanation as to why you believe that this response is correct.
While the "arrest" and detention" questions generally refer to purely criminal matters you never want to leave immigration enforcement out of consideration. I believe that the correct answer to your questions is to disclose the existence of the arrest and provide an explanation in an addendum or in the space provided. Interestingly the I-751 and the I-485 ask about whether the applicant has been arrested or detained without referring specifically to the question of whether the arrest or detention has anything to do with immigration enforcement. But the N-400 specifically asks the question to include the possibility of immigration enforcement requiring a "yes" answer.
The general idea with all of these applications is not to hide anything and to be up front with the adjudication of your applications for immigration benefits. Certainly different attorney can have a different take on what should and what should not prompt a certain response to a particular question. I always err on the side of providing more information that less information because I do not want a client ever considered to have misrepresented anything as a result of a response that I helped the client provide on an application which was submitted to Citizenship and Immigration Services ("CIS") or the Immigration Judge ("IJ").
Ultimately your credibility is a central part of the consideration of most applications for immigration benefits. If CIS or an IJ cannot figure out whether you are being up front or not, it makes the favorable adjudication of your applications that much more difficult to obtain. Yes strategy is important but you never want to put strategy ahead of being up front, clear and truthful with your applications.
So I think that the answer to your question is that the responses on the I-485 are unlikely to create all that much of an issue with the adjudication of the I-751. And if you have any doubt, amend the response so that you are clear and that the response says what you want it to say. Make sure that you are comfortable with the attorney that you have and that you believe that your representative can adequately speak on your behalf. If that confidence is gone, you really need to find someone else to help out because if you do not trust that your representative is going to do the right thing, you are in for a tough time all around.
Get a second opinion if you believe that you need one and do what is right for you, not what is right for the attorney. Our job is to zealously advocate on your behalf. In so doing we must listen, advise and represent - sometimes even if this means we do something on behalf of a client with which we do not agree. My job is to provide advice on the pathways available and it is the client's decision to pick the pathway upon which the client will travel.
You may want to speak with a different attorney.
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I agree with my colleagues.
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