0.5 is a pretty weird limit -- testing it, I found you could easily reduce your size by 2/3 many times without it being an issue, assuming a base size of 1.0 (and rounding):

1.0 * 2/3 = 0.66
1.0 * (2/3)^2 = 0.44
1.0 * (2/3)^3 = 0.30
1.0 * (2/3)^4 = 0.20
1.0 * (2/3)^5 = 0.13

Which means that limit doesn't even support lowering your size twice, the point being, you are meant to be a smaller target (harder to click) if you die lots...