What are the ethics of bringing recruits with a departing coach to new program? Fair to recruit fm old school

Is there a general consensus among the coaching world? If the coach leaves, is it fair to ask inbound students to be released from LOIs to go to new school? Should the coach be hands off. Recent cases: Stanford coach moves to LSU and states that he will *not* try to move recruits. Marquette coach moves to Indiana and trys to move recruits. Is there some sort of standard? Thanks.|||There should be