Being a web designer.
I know way before hand what the boss/client wants their site to be supported on. and it's really not so hard to make conditional CSS to fix sites for cross browser compliance. Situations like this only happen because of poor communication.
Yes IE6-7 suck .... the standards have changed.... businesses wont upgrade until they absolutely have to because it costs too much to upgrade frequently.... this isn't an inconvenience to us web developers... it's an opportunity to show outstanding quality by not having these embarrassing moments. So when you shout "STOP USING INTERNET EXPLORER 6-7" don't be surprised to hear people say "no"