If it’s a new carpet then the area surrounding the stain won’t be dirty, so where’s the problem?
Putting my cynical head on.... be careful when being called out to a stain, rather than to clean a stained carpet.
Sometimes, rarely, thankfully, the client can be looking for someone to blame, even though they caused the stain, but if it doesn’t come out, they could say that you have made it worse and look to you to replace it for them. Trust me, it happens