My latest interaction with a university I have worked part-time at for approximately 20 years involves the survey they send to part-time teachers to gauge interest and availability of schedules. For 18 years there had been no problem and the survey request was sent months in advance.   

Last year, no classes were offered to me. With union intervention, I was able to keep my number of classes the same with a slight schedule change. This year, some part-time teachers received the request survey (all by email) with a 2 week deadline to reply.  The email states that failure to reply before the deadline can be taken to mean that you are forfeiting any right to work there and any classes you have.    

At least one other teacher and I received the email survey the day before the deadline, leaving us less than 38 hours to reply. This is not a suitable time frame for a deadline, but I believe  that the university was hoping we would not see the deadline in time and to avoid assigning us classes. 

This should never ever ever happen at a university. General Union sent a reprimand to the university for these tactics and received a prompt reply that this should not happen again. Hopefully the person who tried this trick was reprimanded by the administration. 

I highly recommend that if eligible, especially as a part-time university teacher, that you request to sign an unlimited term contract. This gives you more protection from losing classes than an ordinary annual contract which you have to sign each year with the university. 

Even if the members had been unable to meet the deadline, they are employed under unlimited-term contracts (UTCs). The union would not have accepted the university using such short notice as grounds to reduce their assigned koma.