Today I encountered the following issue:
I retrieved tags from Amazon for an album that had a song named something like "first/second.mp3". Since my own filenames for that album weren't right, I executed "rename files from tags". During that process, mp3tag created a subfolder named "first" and inside a file named "second.mp3".
While this is not exactly dangerous, I can't think of a scenario where this would be intended. Also, there may be other special chars coming from external sources containg more undesired chars for file naming. Maybe mp3tag should consider these chars when executing something like renaming from tags.
Greetings from Radebeul,