Seat belt light

I sold my Moms 2001 Nissan Sentra to my Aunt a few months back. The seat belt light would sometimes come back on when the seat belt was even latched, now my Aunt tells me the light stays on all of the time. Are there any risks with not doing anything about fixing this light? or shall I tell her just to ignore it? I would sure hate to see her get into an accident and then the seat belt not work properbly.