I have tried it and yeah visually its "working". You can see the boost icon but actually it's not giving you bonuses.I have tried only with XP Boost but I'm prety sure the result with IP one will be the same.
Guys, it works. What he's trying to say is, Change your time not date to 1 year back to 1.1.2013. When clicking on LoL there will be a certificate to ask you to verify whether if this is safe or whatever. Click "yes" If you can find it, Minimize LoL and re-open it. Drag your LoL down abit and you will find it hiding behind your LoL window. Hope this helps!