Can I lend my Mcard to someone else?

No, lending Mcards for any purpose is not permitted as per University SPG 601.13.  Should an Mcard be given to someone else for use and the Mcard becomes lost, it is the original cardholder's responsibility to pay for the replacement of the card.  There have been cases where borrowed Mcards were used for fraud and the original cardholders were held responsible.  It's just not a good idea no matter how trivial it may seem.