I play Seatac almost every week, and have been playing the course regularily for years now. The last two weekends there has been nearly nobody else there, maybe one other car in the small parking area and thats it, when I was out.
I think the gangster boys have gone away for the most part, I havent seen them much this year. Maybe they grew up.
As to theft, just dont bring anything in the car you dont need, and take the rest of your valuables on the course with you.
Parking at the course is no more dangerous than parking at Southcenter mall.
I have been more concerned at Lakewood in the past few weeks.
About three weeks ago, there was a White Center PD car in the lot when I got there, early afternoon. There was no signs of any trouble, the car was just sitting there with the officer inside.
When I got back from playing 18, the police car was gone, but somebody had dumped a stripped Nissan SUV on its axles sideways, in the parking area.
First time I have seen a wreck dumped there.
A couple of weeks ago, also at Lakewood, I noticed a group of four questionable looking characters just sitting in the parking lot, in a beat up little sedan, as I finished my round. They were not golfers, and did not look like they were there to enjoy the park.
It sure looked like they were just waiting for a quiet moment to bust into some cars.
So I think Seatac is now safer than Lakewood.
Worst thing I have seen at Seatac in the last few months is some dudes sitting on the benches at 13 and 14 guzzling beers, but they're just looking to get drunk, not start any trouble.
Seatac is better groomed and more playable now than it has EVER been before, its really a nice course.