This is not true, I have read it multiple times. It may surprise you, but I am not that stupid :-D
This was more a suggestion, what you should add to your guide, for others... person, who never updated wow manualy, will probably not know, that the launcher is executed automaticaly by the patch itself.
Today I made another attempt to update my client to Cata... and I did this so far:
1) I made a copy of my enUS PC 3.3.5.12340 client
1a) I emptied folders Cache, Logs, Screenshots, WTF and all nonblizz addon folders in Interface/Addons
1b) I started the game using wow.exe so the data path in registers would be updated
1c) I blocked access to internet for file Launcher.exe in my firewall
1d) My DataenUSrealmlist.wtf file contains only "set realmlist my.random_free_server.org"
2) I downloaded and unpacked TFIL collection, base_win, tools_updaters and all the patches
3) I executed wow-3.3.x-to-4.0.0.12911WoW-x.x.x.x-4.0.0.12911-Updater.exe
according to your guide, now I should:
copy the TFIL for the patch to your WoW root
-> but there is no TFIL for this patch
-> besides, when I now (client now should be 4.0.0.12911) try to run wow.exe, I get this error
Is it OK, that the client won't run? Should I finish installing all the patches first?