You said it's because of a mix-up when reading documentation, but you said nothing about /why/ changing the write-protect pin's state should work - or why tying clock and data pins together should not.
The more interesting aspect, verified by testing, is that it does work.
In my own testing, SCL to SDA will not work on the T2X, T3X, T4X, T60, X2X, X3X, X4X, or X60. It does work on the T61/X61 and T400/500.
PROT to GND works on all of the above. I also tested it on an X230 (works), but I didn't check SCL to SDA on that machine.
PROT is not the WP pin. They're different. Go read the spec sheets.
The original hack as discovered was PROT to GND, not SCL to SDA. My only speculation was as to why the hack as reposted changed over time.