Edits complete, potential cheats disabled. Issue resolved.

Thanks for the suggestion, I will disable them right now :D

Your right! This could be misleading because the description is talking about unique IDs. Therefore I added a note to the description's text.

if(typeof list === 'number') {
return arguments[arguments.length - 1];

Your solution only consider a list of arguments as a list of numbers.
What if arguments are of another kind ?

eg:

last( "x","y","z" )    // -> "z"
last([0,1],[2,3],[4,5])// -> [4,5]
last(false,true,true)  // -> true
//.. and so on..