kettling police tactics G20 protests

Kettling as it is called is a British police tactic forcing protestors and unlucky citizens into an ever smaller area were they can be contained for anything over 4 hours usually. Like its name suggests the pressure mounts to such an extent that at some time it has to go some time and at this time the police then have due cause to arrest people who just want to get out. Usually these people have little space to move around in and as such no assess to a toilet if they need one exasperating the situation. this makes people less likely to protest in the future and could also be seen as a lesser form of torture as those used by the US CIA