In 14 years of driving it, I can't say I remember a time where I ever got the wrong function while using the single stalk in my truck. There are times when I've gone to turn off the high beam and pulled too far, triggering the beam flash, but I've never turned my wipers on only to trigger the turn signal. There are times, usually when it is really cold, that the multifunction switch doesn't want to work at all, but never does it trigger wrong for me.
But maybe I'm lucky and I got the only multifunction switch that isn't hard to mistrigger or maybe you're unlucky or there's something wrong with your technique. Every function except the wipers is a one finger thing for me, the wipers are three - my thumb, index and middle fingers as I roll it.