Any college student who’s navigated even one semester knows buying a textbook can reveal roguish price markups around every corner.

Their one lifeline from a $100-plus book: the much-loved bright yellow “USED” sticker.

But because of neglect by some Portland State University professors , students may be seeing a lot fewer of those stickers when winter term starts in January.

The deadline for profs to turn in textbook requests for their winter term courses was Oct. 15. Student government president Rudy Soto says that as of last week, nearly three weeks after the deadline, only about one-third of the needed requests had been turned in.

“There are some students who have been pretty pissed off,” Soto says.

PSU bookstore CEO Ken Brown says punctuality is a big factor in the bookstore’s ability to find used texts, saving students as much as 25 percent on a purchase. “If we get those course requests late, we lose out,’’ Brown says.

Soto’s Associated Students of PSU has started urging professors to get their requests in immediately, and he says most “have been pretty receptive” once notified. Gary Brodowicz, president of PSU’s American Association of University Professors chapter, says his colleagues may have been swamped or not notified, as usually happens, about the deadline.

“I think maybe it’s just a workload issue,” says Brodowicz, a physiology of exercise prof who just got his requests in this week. “It’s one of those things that just slides by.”

But the Rogue Desk channels every hard-nosed prof who ever coldly responded to our late-assignment pleas: Ignorance is no excuse.