Does anyone know when to when there will be ID checks at night?

Also, will it go on for the entire semester?

Lastly, how the hell can you get into Les Prince and/or Whidden without getting caught after hours?

One more question, how long/ what is the process needed to allow someone to be a "guest"

Id checks in residence are on Thurs, Fri and sat starting from approximately 10:30-3a.m. during the other time of the week, there will not be any desks up for id check. This is for the entire year. You are allowed two guests per night.
If you want to, you can technically bring the guest in before those hours and that will be fine. However, if CAs are on sweeps of the building and find guests alone wandering in the halls, they will escort them to find their host and have them sign in. Remember, whatever your guests does, you are accountable for it. So dont' sign in people you do not know.
It doesn't take very long. Your guest will just show their id, and just sign their name on the sheet and have a stamp on their hand. That's all.

so by guests, and showing id, does that mean they have to be mac students? or it can be anyone, even someone who doesn't go to mac? as long as they sign in it's ok?

It can be anyone that you sign in, just remember that you are responsible for that person.

If it is a Mac student, they will need to show their student card to get in. If they are from another university, they can show their university student card to get. If they don't have a student card, a driver's license will also work. Just make sure that they have their ID on them, or they will be sent back to get it.

yep. anything with photo id that is legitimate. also remember that guest policy for staying overnight as well. Guests are only allowed to stay overnight for 3 consecutive days. after that they can sign back in for overnight as long as there is a 7 day period in between. Its also good to let your roommate and CA know before you invite any overnight guests.