I am assuming they have 1) cookies enabled 2) Javascript support. At least my stats tell me
IF a sponsor uses cookie-only tracking but has better conversions, then its better to promote it, even if i may lose some sales from the cookie. I take the cookie tracking game as a part of traffic leak game many programs have.
Well what matter for me in the end is not the conversion that the sponsor shows me in the stats. It is the actual traffic I send them and the final amount on my check. But of course many the sponsors know very well that not every1 is tracking their traffic.
As for Javascript - same issue... those stats dont provide cookie stats, since the tracker uses cookie to track

Browser capabilities (last 30 days)
Java Enabled
Yes 1,004,342 98.61%
No 14,142 1.39%
Flash Versions
9.0 695,984 68.34%
9.0 r115 133,712 13.13%
9.0 r47 37,800 3.71%
6.0 24,038 2.36%
8.0 23,845 2.34%