I have no problem with them myself but they absolutely do leave lines sometimes! Yesterday at work we were having cake & a coworker leaned over in tight pants and you could clearly see her thong lines! It was quite surprising & I am not the only one who saw it. Previously, I saw the outline of a thong on a girl in white capris. NO I do not go looking , but she was in the front of a room giving a presentation--a very lonnng, actively-moving-around presentation. All you could hear were snickers from the guys every time she turned around (this was in a college classroom, but you would have thought it was kindergarten). Thong lines are more unexpected, I guess. Both times, I was just thinking, "Note to self..."
Please don't assume you won't have lines if you are in a thong! To avoid panty lines completely, I recommend Jockey No Pantyline Promise panties. But I still like to wear thongs now and again, just for fun!
I don't know, but that lady DH and I saw at the mall a couple weeks ago should NOT have been wearing hers, at least not so that the whole world could see it! She wasn't small, but that makes no difference, except for the fact that her pants fell way below the top of her thong, and when she bent over, her pants were closer to being off than they were to covering any part of her thong. Gross. I'd guess she was in her mid-late 50's at that.
If you have the right size and fit they are very comfortable and you can't even tell they are....um...in there.... Or should I just say, you can't tell you have them on...
The worst drawback with wearing a thong is that having that thing right up your butt interferes with the natural outflow of gas. Im serious...... you have to move the thing out of the way when it happens.