Playing against an irregular partnership, I was East on this hand:
After 3 passes, South opened a 15-17 1NT. Since partner hadn't opened in 3rd seat, I felt that the opponets had a game, and so, I threw in a 2C overcall. Against a strong NT, we play DONT, so that shows clubs and a higher suit. Partner, though, alerted and said that it promised the majors.
North now bid 2D, meant (and announced) as a transfer. South bid 2H, but when North went to 3NT, he hemmed and hawed. He'd forgotten what they played over interference and wasn't sure whether 2D was indeed a transfer. So, he decided to pass!
Now, to me. What do I lead? With all the unauthorized information (partner's misexplanation) and forgotten agreements, I decided to do the "normal" thing and lead fourth from my longest suit. Disaster, of course. Leading a spade would have beat 3NT, but against the club lead, declarer had the first 11 tricks. The whole room was in 4H making 5 (the losing club goes away on a diamond). So that was a bottom.
To put it mildly, my "Disturb Opponents' No Trump" overcall didn't work out.