On the other hand, you have a better argument when the service goes down temporarily. They're more likely to respond quickly if they have paying customers.
That may be fair. In this particular case, I can tell you we respond to Trello outages the same we'd respond to FogBugz or Kiln outages, so your concern should be minimal.
Ah, didn't realize you were a Fog Creek employee yourself :)
http://status.fogcreek.com/2012/10/diesel-bucket-brigade-mai...
I came in to work and was shocked that Trello was offline since I use it as my todo list in work. Then I read the stories as to why and was again shocked when it was only offline for a day or so. Fog Creek are awesome.
We were only offline for a few hours. Self-imposed (and turned out it wasn't necessary but in the fog of war at that moment, was the decision we made).
Nice, even better than I thought, after I saw the news I don't think I checked again that day, didn't seem likely to me that in all that chaos that Trello would be a priority. Happy to be proved wrong of course.