It's because so many workers are always coming up with reasons why they "can't work" which forces the manager to constantly adjust the schedule. So it's pretty much impossible to schedule a retail shift more than a week out.
Always somebody with their "aunt in the hospital" or "I tweaked my back" or some such nonsense. I've heard just about every reason imaginable for somebody not to come into work as scheduled.
I've only had one sick day in 30 years so I don't have a lot of sympathy for people who are allergic to work.
I can't disagree with you, but I think you put your finger on exactly why the Starbucks scheduling software is such a bad idea. Scheduling in the fast food environment will always be more art than science. It is unrealistic to think that you can account for every eventuality in your software program. The proposed fix of adding additional scheduling rules into the software will only make the problem worse (they need to give their managers more scheduling flexibility, not less).
Humans are not machines. They are all different and everyone has issues of one sort or another (those rare humans who don't have issues won't be working at Starbucks very long because they will find better jobs).
“I’ve only had one sick day in 30 years so I don’t have a lot of sympathy for people”
That’s why you have no sympathy. One of these days, you’re going to grow old and your health is going to decline, and THEN you’ll understand what it’s like to have poor health. Until then, you can arrogantly piss on the ill and sick.