Is making super deep safe spots using log off emergency warping mechanics an exploit? I don't think CCP has classed it as such but I've heard rumblings that they are changing the mechanics to prevent it from occurring in Tyrannis which I oppose as I think they are far too restrictive with the game mechanics already. If I want to warp 100 AU in a random direction towards nothingness... LET ME!
But I digress...
The utility of ultra deep safe spots is unquestionable, even if they are not perfectly safe due to the probing mechanics we have now. If you have a ship with a cloak any old safe spot is good as the next. But if you are uncloaked or are cynoing in a fleet, ultra deep spots are better because they are less likely to be probed out in case of the former and take precious time to warp to in the case of the latter.
And when you have a supercarrier that cannot dock, an ultra deep safe spot is a good idea to jump into a system so you have time to warp away and cloak up before any curious hostiles arrive. Of course, as soon as that cyno beacon shows up on everyone's overview many AUs out of the normal system space, they will bookmark it and it won't be so safe next time so having multiple deep safes to use is always a good idea.
Last night I had two 20 minute sessions which I decided to dedicate to practicing the making of these ultra deep spots. It took a few false starts but eventually I was getting it to work and before I knew it I was over 100 AUs from the nearest celestial object. Excellent. Now that the process is understood I can make some more as its always good to multiple options and backup plans.