I was in a knifes only ctf server for about two hours.
I started by playing seriously, but eventually grew tired of it. I then started to just run to the other sides base and just dodge people. It was funny how they desperately tried to kill me. Occasionally I made a kill or some /pwn :ing.
It was good training against knives and at the end I could just drop my knife, run to their base, dodge a few knives, grab one and kill the efc.
It was just great fun. If I got the flag I walked away and threw it somewhere. If I saw an efc I started hunting him down.
One of my favourite moments was when I noticed an efc heading for their flag (not captured) I threw my knife, missed and grabbed their flag just as he touched it.
I suggest you try it sometimes. It's great dodge training.
And it's great fun