Yes but there is opening yourself to channel and then there is a quick unintentional use. If you notice before Rand became a channeler, fully aware of what he was doing and willing try to embrace the power, all you get are the side effects from channeling (the taking chances etc,,) but not the filth feeling. After book 1, when the using the power and the side effects happened near the same time, all he gets is the filth. The difference is he knows he can channel and needs to embrace the source to channel. Just like the women who are starting to channel never seem to notice the warmth of touching the female half until they survive the side effects and become aware what they are doing. A wilder like Nyn, had she stayed in the Two Rivers, never would of felt the feeling of opening herself to the source since she had built up a block, so it might have to do with you have to open yourself up to the power to feel the good or bad.
In one of Rand's lives in book 2 I believe he was a member of the Queen's guards and was lucky, he thought later he understood why but he didn't care. He was suffering from touching the male half but was basicly a wilder and it was never said he was feeling the filth. So I think a lot has to do with someone who channels but doesn't really know it or is never trained how to do it aren't fully opening themselves up enough to feel the filth or warmth. They are incapable of doing anything more then a quick touch of the surface. It's possible Rand would of started to feel nausea when he accidently channeled and not probably not understand why. But there seems to be a difference between inadvertently channeling and intentionally channeling.
Dragonmount.com is a fan-maintained website dedicated to Robert Jordan's Wheel of Time fantasy series. It is an online community of people from all over the world who have come here to experience the series to the fullest.