Is police in schools and colleges really common in the US?

I spent 26 years working at a university with over 49,000 students and over 7,000 staff and faculty. Big universities have their own police forces, which include security guards. The police have to pass the same certification as regular city police. The security guards don't. Here are just some of the things they are needed for: * Patrolling for suspicious activity by outsiders. This can be anything from stealing bikes, unguarded backpacks, and cell phones, up to and including robbery of students at gunpoint and rape of female students or late-working faculty. While these latter two crimes are infrequent, yes they happen. * Responding to bad student behavior, like being drunk and disorderly. * Patrolling for students with possible mental disorders who might be trying to cause themselves harm. Or responding to incidents of mental disorders. When I was a student there, prior to being on staff, one girl tried to go after her roommate with a hammer. A 20 year old resident advisor is ill-equipped to handle such a situation. * Offering security escort services to students studying late at the library or needing to leave campus after late classes. One has to call and request this service, it's not automatic. * Providing security at events, in case people get rowdy at football games and such. * Giving talks to students, staff and faculty about what they offer in terms of security services and what to do in particular situations, like if there's an active shooter. * Opening doors after hours after verifying ID and confirming the person's right to go into the building and/or room in question. * Delivering cash or checks across campus. When I was operating a consortium on campus, members paid by check, but I wasn't allowed to take the checks to my business office across campus. Only a police officer was allowed to do that. * Security escort in the case of a sudden firing where there might be risk of resistance or retaliation. They just go on in, hustle the person out the door and to their car, and wave bye-bye. * Helping city police solve crimes when they occur. I find it difficult to believe that large universities in other countries don't have similar problems and don't also have security of some sort. When you have a population the size of a small city, with most of them paying large sums of money just to be there, why wouldn't you need safety measures? Would YOU move to a place with a population of over 50,000 people that had no cops?