I can't see why they'd need to induce...? My midwife didn't even test for it, said it was a waste of time as the results mean virtually nothing, unless (like Trillian said) you are sick from it. I can see why they'd want to kick start labour if your waters were already broken, but I don't see the reason to induce for the sole reason that you tested positive for strep b.
A lot of OBs dont routinely test for it either and take the approach where you look for warning signs when you are in labour. I'm going to be talking it over with my midwife next week to see which we will go for.

TBH I'm more worried about a -ve results at the test but actaully having it on the day.