I've never thought it was an issue.
It's common for advanced programs to have options, and to save any changes users make for the next
time the program is fired up. Such options are colors, fullscreen or not, sound on or off, etc.
Also, a temporary file is often created when retrieving files, like "shell /c dir >temp.dir", unless
one uses the SpriggsySpriggs pipecom library. Some people think it's good manners for the program to
delete such temporary files, but I think it's nicer that the code never shells out a "del" command or
contains a KILL command.
One has to eliminate all disk output if it's known that the code must run from a CD or write-protected
device, but that's a bit rare.