It never bugged me that she was sucking on plastic. I was just glad I had it because it was the only way I could get DD to latch onto my flat, inverted nips. Plus, I knew DD would be getting a bottle at daycare (when she went at 3 mo.), so it didn't seem that different to me.
I cleaned mine after every nursing session. I actually ended up with 2 or 3 of them, because I didn't want to have to wash them in the middle of the night! I just hand-washed them with dishsoap and let them air-dry on a clean paper towel.
The sheild in no way encouraged me to pump. In my mind, that would have been even more work, because I would have had to clean all those pump parts and bottles!
OP, I don't really understand your comment about the sheild causing leaking... can you (or someone) clarify? I never had any leaking with the sheild. Now, I did wear breast shells to help draw-out my nips and they caused tons of leaking! Which is probably why I stopped wearing them.
Mom to retired nursling Lily (6/22/07) and wife to my wonderful DH since 3/19/05
Baby Aerick is here! Born at 40+6 on 5/16/10