- possible dependencies uncovered and acknowledged late in delivery cycle
 - incomplete testing of reasonable customer deployments
 - not really being sure of your code to handle these contingencies.
 
- if it's needed
 - whether it actually fixed the special cases intended
 - whether it really is "orthogonal" to other parts of the software
 - the details of how it works
 - why it's as "safe" as you feel it is
 
