There are only two scenarios where banning pick intent is against the Code

This needs to be more visible than a comment, because it's pertinent people don't accept misinformation at face value.

Regardless of your intended champion, it's only against the Summoner's code (and only the rule about supporting your team) for an ally to ban them if:

• You are First Pick or
• First Pick has agreed to trade you the champion.

In all other cases, the risk of the enemy getting the champion is enough to warrant banning them, especially if it's an extremely high priority pick/ban. You may be sad if you're last pick and an ally bans your Akali, but that doesn't mean you can file a false report.