So glad I did! My small LilacCup sealed perfectly and I had no leakage at all! I thinks I've been a little obsessive about emptying it, because I was worried about the small capacity, but otherwise all has gone well. I even went out dancing with everyone after work and didn't have any trouble. Used it overnight too, with no problems. I am so excited!!!!!!
I don't know if anyone is interested, but I might sell my large LilacCup. I bought a mix double pack, really thinking that the large would be better, but the small seems to be a better fit for me. I'll definately give the large another try (I really want the higher capacity!) but if I can't get it to work, then I may as well pass it on to someone who can use it.