Hmm, great question. What I do is I run one of them in incognito when I'm logged in and I've never had any issues nor experience a soft ban, at least I don't think I have. Don't take my word for it though, but in my experience this is what I've done and I'm fine. Hope this helps.
I have done it in the past. I had no trouble with playing N Crave on both Swagbucks and My Points. My only caution is N Crave can slow down your computer.