What is a legit derailment?
Our first answer is that if you want the brightest possible bright line, you can opt in to No-Excuses Mode! In that case, the answer is that every derailment is legit! More on that below.
Otherwise, the theoretical ideal is that we only charge you when you when you could have met the goal and didn't. For example, you saw our reminders, you decided that you really don't feel like going to the gym tonight, so your goal derailed, and then we charge you for it. If you actually did go to the gym yesterday, but you forgot to update your gym goal with yesterday's data, that's (probably) not a legitimate reason to pay up! (Unless you decide that entering data is a part of your goal, which some users do to keep the bright red line nice and bright.) If that happens to you, you can reply to the legitimacy check email to let us know, and we can undo the derailment and stop the charge.
Likewise, if you've contracted a highly infectious disease and are not allowed to leave the house, you probably shouldn't go to the gym, so that's also not a legit derailment. Reply to the legitimacy check email to let us know. And so on.
It is generally up to you what qualifies as "not legit". We'll probably inquire about what happened, if you haven't given us much detail in your original email, or check in with you if it sounds like it might undermine your use of Beeminder in the future. The important thing, we would say, is to be consistent: no "just this once it's okay to stay home because it's raining, but I don't want that to be an excuse in future". It should always be legit or non-legit if the same circumstances come up again in future. In the end, it's up to you and we'll believe the reasons you give us.
One thing to keep in mind is that you're probably not going to get a lot of value out of Beeminder if you're frequently derailing on goals and sending us weaselly excuses about it to avoid paying up. Calling not legit a lot means the real sting is totally diluted by all the times you decided not to get stung. That's okay, though — we're not the only game in town, and there might be an app out there that suits you better!
If you want us to be very strict about your excuses instead, you can turn on our No-Excuses Mode under the Commitment tab on the goal's page.
If you derail on a goal that has No-Excuses Mode enabled and reply to the legitimacy check, we'll remind you that you have No-Excuses Mode set up, and refuse to cancel the charge / do a refund... except in one circumstance: if something buggy happened, so the derail was our fault or the fault of an app we connect with, then we'll chat about that and sort out something fair.
You can turn No-Excuses Mode on and off at will. If you turn it off, we'll be able to see when you last turned it off and that information will be included in your legit check emails, so it'll be very obvious if you just turned it off to be a weasel!
Keywords: legitimacy check, legit check, derailment notification, weaselproofing, weasel-proofing, no-excuses mode, sick, ill, illness, can't do goal, what counts as legit