The seller is local and only posting the snakes for sell in local fb groups. Not any reptile based groups in which she had announced that she was having deaths that were found to be a paramyxovirus?
Take screen shots of the forums where the seller stated s/he had snakes die of a PMV and post the pics on the ads. As Skip noted, PMV's can lay dormant for a very long time. This seller is being irresponsible and putting other people's collections at risk.