By the "letter" of the law, yes, but it's the foreigner who pays the fine. If they're only going to be here for 10 days, I can't see where there would be a problem. It's when you go for a visa extension that you may have a problem. My son arrived uninvited to his mom's house in Hang Dong a year ago and camped out for six weeks attempting to bully her into forking over all her money. My daughter in law owns the house but could not have possibly done a TM30 or been responsible because he was not supposed to be there. Also, despite numerous efforts to point this unpleasant situation out to Immigration police in hopes of having him removed, nothing was ever done and no one was fined. I hope this is directly related to Immigration. The point is you need the TM 30 stub in your passport IF you have to do an extension or something like that. Nobody is going to come looking for anybody unless perhaps there's a dead body involved.