Has anyone ever done this before?
For example, you are a senior in college applying this year. You get grades back from first quarter or semester. How do you submit them to the school? Do they have to get AMCAS verified? If you are waitlisted at a school, what is the protocol for sending them new grades?
Most of the time, schools will request a final transcript when you are accepted. If you are on a waitlist, it is highly unlikely that your grades from one semester/quarter are going to get you off the waitlist. In general, when we have made a decision to place you on a waitlist, you will get off that waitlist when and if a seat opens for you. In short, you are not in competition with others on that waitlist or with others who are still in the application-review pipeline process.
In short, we don't review any unsolicited correspondence from an applicant which is the same policy that many schools have adapted. This policy however, is not the same for all schools. As others have suggested, you can send an e-mail to the schools that you have been waitlisted and see if they have the same policy. If your grades are good, it can't hurt but if you are planning to take coursework second semester, and you end up accepted,you are going to have to pay for another official transcript when that coursework is completed.