Some idiot painted the tomb of Marie Laveau pink using latex paint. The unknown vandal covered up all of the "x"s made by those seeking out the aid of her spirit. It's also believed that if the paint isn't removed that it will end up destroying the tomb as the latex paint traps in moisture.
Note: This was probably some idiot who promised to paint her tomb if she fulfilled a favor or petition. The reason I say this is that the paint job looks nice and was obviously done with care. It's just that that the person who did this is a complete moron and idiot.
Addendum: Two weeks prior to this incident a mentally ill homeless kid was busted painting tombs with latex paint. He didn't like the "graffiti" and claimed he was painting the tombs to protect them. The natural suspicion is that it's the same kid who painted Marie Laveau's tomb pink.