TheLoadedDog - You are absolutely right. I know two blokes who failed to gain custody of their kids when they were by far the better parent. One has since managed to win back custody through the courts but it was a long, long fight (we were down the pub celebrating his success about two weeks ago).
As causes go, Fathers 4 Justice have a very good one and, over the last couple of years, have gradually been building up a great deal of support through awareness campaigns.
Stunts like this, however, do them no good at all - yes they increase their profile in the public eye, but they make it very hard for Politicians to back their cause without looking like they are supporting an extremist group.