I'd just cut your own SIM to be honest. You have a new one coming anyway!
Using someone else's wont hurt though if you're mega desperate. I'd rather not myself, but I'm a bit weird about things like that.
True I could cut the sim down but if incorrectly done would leave me without a phone lol
But yeah if I put someone elses Sim in it would always feel like its registered to them or something similar. Why does a Sim even need to be put in to activate it anyway?