Complimentary tickets are fine. The real issue here is: are they really complimentary, or is it a quid pro quo? Generally, if there’s a good foundation reason to be there, in particular being recognized, you can go.
Self-Dealing and Conflicts of Interest
This Content Collection defines conflict of interest and self-dealing in family philanthropy, and highlights the most common problem areas, including: excessive compensation, tickets to fundraising events, and overlapping board members.