There is a slightly increased risk but overall I'm not too worried about it. Is not that both the DEC and SPS will decrease in the pool. The pool allows people to trade in their SPS for DEC or trade their DEC for SPS. In perspective my position is less than 0.001%. If someone trades 289200 DEC for SPS my DEC count may go down by 2.892 DEC and my SPS count will go up by 0.43.
I could be off by a decimal point but the short version is if I lose DEC I gain SPS. If I lose SPS I gain DEC. Since I use both in the game its not a big deal and because my percentage of the pool is so small the risk is also very small.