Is this unethical, or just how the grooming industry works?

I’m a newly graduated groomer and recently witnessed a situation that has me questioning what’s considered normal in this industry.
There were three students in my class. One student’s employer paid for their entire grooming course and equipment. The employer signed the training agreement with the grooming school and invested thousands of dollars with the understanding that the student would return and work for them for two years after graduating. If the student left before then, they would be responsible for repaying the cost of the course and equipment.
Shortly after we graduated, on their very first day back at work, the student handed in their resignation and said they had accepted a position with the grooming school where we trained.
From the outside looking in, it feels strange that a business would pay the grooming school to train an employee, only for that same school to end up hiring the student immediately after graduation. Whether you’d call that recruiting or poaching, it raises some ethical questions for me.
At the same time, our instructor asked the graduates if we’d be willing to come in one day a week over the summer to continue building our scissor skills. The idea was that we’d gain more experience, but it also helped because there weren’t any new students enrolled to assist with the dogs. Two of us agreed, while one didn’t.
Now I’m wondering about both situations.
Is it ethical for a grooming school to hire someone immediately after training them when another business paid for that training?
Is it ethical for a student to leave on their first day back after making that commitment, even if they repay the costs?
Where do you think the line is between valuable mentorship after graduation and unpaid labour that mainly benefits the school?
I’m genuinely interested in hearing different perspectives from salon owners, instructors, and groomers.