I went to look for the auto-saved replays from the two contest Rule 1 levels, and the filenames were all in the form sXXX.txt, where XXX is just a number that increments with every replay saved. The files being text files does somewhat mitigate the problem, but still - why not use the level filename, possibly with a timestamp?
Autosaving in C++ Lix is dumb, yeah. I haven't touched the feature in 5 years.
This is fixed in D Lix exactly like you suggest.
-- Simon