So you basically distribute a binary of which you dont know what its doing in the background, and which can clearly harm the OS? How come you trust the author like that?
That author could in theory have coded a hidden keylogger in there, or something like that..
The author is also the author of StereoPhoto Maker which nearly all if not all users of SDM also use and have been using for years so there if plenty of reason to trust him.
However unfortunate the accident, this could have happened with any software that is able to do formatting or partitioning including the OS's build-in tools.
Implying that malicious code could be included is like you say "theory" which is true for any software and that is why everyone should have an up-to-date virus scanner and use good judgment as well as taking extra care and double check when using potentially harmful software.