They can alternatively accept the InMail and mark it as appropriate. This will keep the InMail sender's score positive. Most of the time, when I send an InMail, I'm fortunate to have sent it to someone who is courtious. Once in a while though, I send an InMail to someone who is cranky and likely would be cranky if Publisher's Clearing House showed up at their doorstep with a $1,000,000 check.
Thank you for contacting me. At this time I am not interested in leaving my company since I am currently involved in an ArcSight deployment project. Should other opportunities come up, please feel free to contact me.