Alright... I've done a little testing on this. Removed my mods for the testing as well to make sure they didn't interfere one way or the other.
Made a household of 3 YA sims.
1st Sim - Joined journalism career.. could check in just fine.
2nd Sim - joined lifeguard career.. checked in just fine.
3rd Sim - became self-employed writer. Check in caused the game to freeze, which actually startled me a bit since I thought I was free of this bug - apparently not, lol.
I really think the answer is something to do with being self-employed, but like Crin said, there may be another factor at play since she had a self-employed diver who had no problems. Totally strange. ;P
