I used to pk, especially in castle and sards. People always arrow their friends for easy kills at 0.5. These are the strategies people love to use in towers. Kills going to the last registered hit from a non-ally/item/spike/baddy would definitely make pk fun for a lot of people, especially for me. It's lame when people deny kills, and I stopped doing that.

Sards
Even though I used to run away at 0.5 - 1hp, people do this all the time now.
You get their health low, and they run away. They either run away into the spike room, or they leave through the entrance, enter their house, and bomb themselves.

Castle
When at castle, people will get kills in the flag room, run outside, enter house, and die. The defenders don't get the kill, because of this, and a lot of defenders will do the same thing.

Destiny
People will fall through the holes, and kill themselves with the spikes.

York
Run away into the barrel room, and kill themselves with the explosions.

Other than that, the other towers like MoD, Swamp, and Snowtown were never that crazy on denying kills through suicides.

Just make the kill go towards the pker, not the guildmates, allies, or spikes.
It's annoying when you are getting kills very slowly, because every defender just keeps running away, or giving the kill to their friends. I got that person from 3hp to 0.5, and the kill goes to their friends. Ridiculous.

You can keep doing your strategies of having full hp in flag room, just give the kill to the person who actually worked for it.