I think it could work but I'd do this: hand apply the glitter (and use the smallest flake size you can buy) to the first coat of shellac, do it while the shellac is still tacky. Then "entrap" the glitter with all of the many coats you will apply to the tape. You (or she) will have to keep an eye on the wear of the shellac and re-apply fresh as it wears away or glitter could end up on her hands...and elsewhere.