Well, who better to answer my post than myself!

Checking in to SAN at 3 pm - a full three hours before my flight - I found the line at security in Terminal 1 to be exactly 0 people. Yes, I walked from United check-in (no line there) directly to the x-ray machine (briefly telling the TSA guy that I had no liquids of any kind in my bag (and that I'd also urinated recently).

Since there was no one there, I chatted with the TSA agents about the lack of line. They said Terminal 2 had bigger lines, but it wasn't so bad by the end of the morning rush.

So, there was no need to get worked up about it. Good luck to the OP!