If you’ve followed an index link and suspect trouble:
Better safe than sorry.
The intitle:index.of search operator is not illegal by itself. It is a legitimate Google search function. Here’s how to use it ethically:
Legal uses for "index of" searches:
Example of a legal search:
intitle:index.of "prison break" filetype:pdf (for press kits, scripts, or study guides that are legally shared)
But using the same operator to find .mkv or .mp4 files of Prison Break is copyright infringement.
Since there is no quality control, the "Prison Break" episode you download may be: