[nauful]

I've had to disassemble client applications several times to investigate issues with server compatibility when generic error codes and crashes don't give me any hints. Network debuggers don't help when the issue is caused by incorrect client processing and you only wrote the server.

In all of those cases modifying the disassembled executables is not an option (both legal and must work with original installs), but was invaluable in creating workarounds on the server side. It would be simpler to submit patches to the original vendors but enterprise companies generally ignore them or put them on the back-burner for some unspecified future release.