Checker throws exception if not qualified

from https://www.geocaching.com/help/index.php?pg=kb.chapter&id=127&pgid=780

2.15. Challenge checkers
Challenge caches published after April 21, 2015, must include a link to a Project-GC challenge checker. This requirement is ongoing for the life of the cache page. Visit Project-GC’s FAQ to learn how challenge checkers work and how to create one.

Challenge checker requirements
Your challenge cache may be disabled or archived if the associated challenge checker does not work properly. Make sure that your checker and cache page meet these requirements:

* A challenge cache page can only include one challenge checker.
* The GC code on the challenge checker must match the GC code of the associated challenge cache page.
* The challenge checker must verify that a player does or does not qualify to log a challenge cache as found.

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The Challenge Checker for https://www.geocaching.com/geocache/GC81PVG throws an exception if you don't qualify rather than displaying a message. I say this violates the challenge checker guidelines, the cache owner says it's fine. Thoughts?

As per this thread, the CO requested an investigation and I've resolved the issue a few minutes ago.

> I've resolved the issue a few minutes ago.

Would you please like to comment on whether this did or didn't meet guidelines, in case it comes up again?

As per the thread listed: there was a bug in the script used to create checker. Nothing the CO could have predicted and nothing to do with guidelines. And as I mentioned above: the CO did report the problem and I fixed it.

My original question was not whether there was a bug in that particular script, but whether guidelines for geochecking scripts permitted a script that threw an exception when the cache requirements weren't met rather than printing an explanatory message.

That seems like a simple question and nobody has answered it.

Let me answer it in a different way then: checkers should never throw exceptions due to bugs. It should return yes or no, depending on whether the user qualifies or not.

It is against guidelines if the checker can not give the answer. The proper way to deal with this is to fix the checker.

This question may pop up in the case when the checker can not give the answer fast enough. For example, if it takes too long to process the data to find the required combination, the checker may time-out before the answer is found. This could lead to archiving the challenge if the problem can not be solved.