[Goose]

depending on course sequencing in any given major they may have to take required course in spring quarter senior year.  As a chemical engineering major I had at least one, and I think two, required chemical engineering classes that quarter

Yes, that does happen, particularly in engineering. I don't know if it is still true, but it used to be that the School of Engineering got around the maximum number of "required units" allowed by the University by requiring classes that had prerequisites that were not themselves required. I don't know if you were planning to not attend in the spring, but I expect that if that were the case you could have altered your schedule to get those classes early. It might be that classes taught every other year in the spring would be unreachable, but otherwise it is usually possible to work around this issue without even getting some kind of substitution approved. Given the "designer" nature of many of the current majors, I expect this is a very rare problem now.

[Goose]

depending on course sequencing in any given major they may have to take required course in spring quarter senior year.  As a chemical engineering major I had at least one, and I think two, required chemical engineering classes that quarter

Yes, that does happen, particularly in engineering. I don't know if it is still true, but it used to be that the School of Engineering got around the maximum number of "required units" allowed by the University by requiring classes that had prerequisites that were not themselves required. I don't know if you were planning to not attend in the spring, but I expect that if that were the case you could have altered your schedule to get those classes early. It might be that classes taught every other year in the spring would be unreachable, but otherwise it is usually possible to work around this issue without even getting some kind of substitution approved. Given the "designer" nature of many of the current majors, I expect this is a very rare problem now.