This "should not" work this way, at least from my perspective as a consumer of this great product that produces Shape5.
Let's say I have "no" twitter account, as indeed I have not got an account with that service.
Then I came to ~ Fusion Shape5 Options
To make a couple of click, and "left blank" the field ~ Twitter Link
Then I go down and I click on Save Changes.
Of course, I'm quiet to sleep, thinking that I solved my problems of the day. The next day a friend called me saying he has tried to get my New Twitter Account but always get this linkhttp://twitter.com/shape_5
And he asks me, who they are, are they? promoting your work on common-law on the internet.
There will be a way to resolve it from "child functions.php"