No, it does not mean you automatically go on a list, but you "might" if you get a large quantity seized and then they will decide if you are worth it to the local police department to go after. They are more concerned with sources than buyers, but some local departments can be hardcore, specifically in college towns(at least in Texas).
I know a few people who got over 10 letters in the mail and still used that address, but the packs they had seized were very small.
A large order can get your door kicked in, but that is very unlikely.
I actually have a few letters around here somewhere, 3 IIRC over about 5 years, but this was years ago when things were less controlled.
Make no mistake things are getting more strict, so use proper precautions when ordering anything.
