Thanks for sharing that story, Ron! It made me wonder if there isn’t a way to automate that backup check.
Turns out, that ChronoSync has a “Validate” function (emphasis mine):
The validator function compares the selected file or folder pair and verifies that the file data, resource forks and metadata match between the two. This includes verifying the data via bit-for-bit compare or checksum, depending upon the target connections.
Sounds like that approach is much more thorough, more trustworthy, and less tedious than any randomized manual testing could ever be.
So there’s my weekend project… 
P.S.: TidBITS Talk still rocks. Of course. 