Unfortunately, yes.

On that note, I've been meaning to ask other p2poolers what I should do about that, if anything. My nodes currently comprise around 46% of the p2pool hashrate. This means I could perform selfish mining attacks if I wanted to, and if I boosted my hashrate a bit, I could 51% attack the p2pool network and get 100% of the shares. Mostly, this happened because p2pool shrank from 2 PH/s to 0.8 PH/s, not because we grew much. One way of dealing with this issue is that I could take some of my hashrate off of p2pool (and maybe solo mine instead), but that would make p2pool blocks even rarer. (I think my nodes have found the last 4 p2pool blocks.) I could also maybe spread some of my hashrate among other nodes, although this would reduce our revenue. Or we could get more people to mine on p2pool, somehow.