Every university has a non-discrimination policy usually stating that it allows equal educational access to all students and it's an equal opportunity employer. This policy is important because without it, administrators could select students based on their racial or socio-economic backgrounds, or refuse to hire candidates because of their gender, race, or religion.
Most universities have policies against faculty having relationships with students if the student is in the faculty member's class. This is to prevent accusations of sexual harassment, which is any unwanted sexual attention or forced contact between a faculty member and student. This is a key policy for many reasons. First, students deserve to be able to pursue their studies without fear of unwanted sexual attention. Second, sexual harassment lawsuits are prohibitively expensive for universities and the lost revenue from even false cases takes away from the university budget.
Each year, most faculty travel at least once to present at conferences or symposiums. Universities reimburse faculty members for meals and other travel-related expenses, with states setting limits for public institutions regarding how much can be spent per day for hotels and food. The travel policy prohibits faculty members from misreporting their expenses or accepting honorariums for attending conferences. This policy keeps faculty spending in check, which in turn keeps the university budget balanced.
The rules for gift giving are very specific. Faculty can only accept gifts of a certain monetary amount from students, usually no more than $25. Also, faculty cannot accept any services from students, such as help with grading, free food, babysitting or any other favor, because this might lead to claims of harassment. Faculty also can't accept money from another institution if they're travelling on university business, a policy that prevents conflicts of interest.