Sponsors should use HTTPS affiliate admins
 

:2 cents:

only seen one recently that wasn't for a dating site, seeing a lot of these:question

i'm promoting all nats, in-house, mpa3 and other script-running affs
most of them (like 95%) run http by default, some of them have https if you try, but w/o certificate, what's not a problem. https for affiliate admin should be a standard and script developers should get into this

Why are you worried?

Someone looking at your 1 sale a pay period?

I'd be more concerned with how the site is tracking your traffic. How much they shave/scrub your leads/sales etc.

you can sniff routers (and steal passwords)

It would make sense but it's probably not happening. There is some additional cost (however small) involved and that is the deal breaker for requiring it.

Since the risk is only for the affiliate, no program(or very few) will ever spend a dime on SSL certificates for their affiliate program.