Is there a reason why I can not spy on players in express on last day of set?

there could be a few reasons

most likely is the end of set GDI protections. for the last 40 or so turns(server dependent i think, cant remember the exact fluff) there is a creeping NW limitations that makes the range of NWs you can hit smaller and smaller. Designed to stop end of set suiciders

or you could be out of ops.

I was left alone this set I have 35 missiles unused such a waste :(

Actually 41 missiles even more depressing

Thanks mrford for the answer. I've just never tried to spy on last day of set.

fluff

interesting