That would fail on a user supplying a multiple where you don't expect.
> If multiple fields are used (i.e. a variable that may contain several values) the value returned contains all these values concatenated together with a newline character as separator.
In GP’s defense, there is no standard behavior in the spec for handling repeated GET query parameters. Therefore any implementation-defined behavior is reasonable, including: keeping only the first, keeping only the last, keeping one at random, allowing access to all of them, concatenating them all with a separator, discarding the entire thing, etc.
