Good Lord, there's just some people on this planet on whom a work ethic was never bestowed. Read something a year or two ago regarding generational differences, attitudes toward employment expectations and societal expectations, and the upshot was that the youngest generation of workers (twenty-somethings) overall have a greater tendency to believe themselves exempt from what had been common business practices for decades. Now, don't everyone go freaking out, saying "I'm not like that", I'm talking about a broad-scope, nationwide phenomenon whereby those children raised with excessive praise just for being themselves and raised to believe they are special just by their very existence (super self-esteem) have turned into adults who aren't taking responsibility for themselves the way generations before them have done.
These two employees are the very example of which I write. Who knows, maybe they're each in their forties, but they sure sound like the generation of people sociologists are worrying about. They feel it's fine to arrive late, because the job will wait for them. Totally unrealistic, but that's the world they live in.
What to do about it? Don't humor them, don't give them a dozen chances; it actually sounds like they got WAY more opportunities than they ever deserved. Makes it worse for the rest of us who actually DO show up on time, ready to work. This is timely for me because I see it (the "I'm special, everyone owes me" mentality) myself, and it infuriates me.
As far as the original question posed, my facility has recently POSTED its official policy, probably in response to the aforementioned problem. It says that if anyone is clocked in 8 or more minutes late, it's LATE, and if that happens four times in a two month period, it's habitual, subject to personnel action, etc etc. Doesn't leave alot of room for the slackers, so we'll see!
**just noticed something in the original post: those employees each live with their parents, no kids....yep, the very definition of the Super Self-Esteem club, lol! They haven't fully become adults because they are still in their childhood roles, and probably will be until some reality slaps them in the face. Like living on their own, rent to pay, and such.