What are the consequences for parents allowing underage piercings?

Well it'sbasically there* (* that being the parents issue to deal with ) problem, however most body piercing studiOS won't provide some piercings to minors regardless of parental consent or not. It's a matter of ethics and what is acceptable in the community where the studio is located. Most cities have bylaws preventing studiOS from providing certain services to minors. Minors don't aways listen and follow instructions that's why there are age limits set on most piercings to prevent issues from occurring.