Brain teasers are not the norm in technical interviews in the computing industry. The norm are technical questions aimed at trying to test knowledge and skill at something the interviewer sees as important (which may be a “big picture” topic).
Yes, interviews have limitations. (So do references.)
The applicant’s college name mostly says something about their parents’ financial circumstances and choices and their high school achievements. Do you consider those to be reliable indicators of their current ability to do the job you are hiring for and future ability to do anything that you may want them to be able to do in the future?