In my freshman year of high school, we had a policy they referred to as "Lockout", wherein if you are late to a class, you automatically are not allowed to go, and instead have to go sit in one of the old, unused bungalows for the entire period. It basically gave any kid a free excuse to get out of a class they didn't want to deal with that day by just walking really slowly. Absolutely retarded.
In addition, I've always found the idea of suspension (and, up to a point, expulsion) to be entirely illogical. A kid breaks a rule, so you punish him by taking away his education? Not only are you basically condemning the child to be more stupid than he already is, but you're also likely taking away one of the things that most annoys him. Really sharp work there, school system.
Of course, the things you can get suspended or expelled for vary so much as to border on the ridiculous. I was suspended only twice in my years of public schooling - once because I had a little grooming tool (the kind with a nail cleaner/filer thing) that apparently could have been used as a weapon, the other time for breaking a kid's nose in a fight that he started, and I finished. Both times I was suspended for a week. Tell me that makes any sense.