Yes session cookies can be easily modified by a third party code,as the cookie only loads in the browser through the server,they can be modified but not quite in your case.I would know more if your faucet was actually working,not sure if you're editing it but this is what I get when I tried to access it
Fatal error: Cannot redeclare getRandomWeightedElement() (previously declared in /home1/ab44276/public_html/mili_staging/wp-content/plugins/exec-php/includes/runtime.php(42) :
eval()'d code:5) in /home1/ab44276/public_html/mili_staging/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 14