Do you mean is there any way you could? Yeah, you could take one of the save game files and open it up. You could also packet sniff the data while someone is logged in and figure out what they're doing. Of course it's possible to cheat.
Maybe you're asking if it's easy to accidentially get information you shouldn't have? That would be a reasonable concern but you'll be happy to know that the answer is no. You can tell when people log in and out, and what their scores are (all information that appears on Civstats anyway if you use that) but you can't get any information outside of that without really trying.