I actually got in trouble more for leaving a Kindle and a game system in a bag on my last trip than on the previous trip when I accidentally had a utility knife

I actually got in trouble more for leaving a Kindle and a game system in a bag on my last trip than on the previous trip when I accidentally had a utility knife in my bag's pocket. I was sure I was about to be detained for the knife, but they simply told me I could leave it there or exit the security line and mail it back to my house for a $15 fee. I took that mailer option, walked out of the line unescorted with a knife, filled out a mailing form, put the knife in the bag, and went through security again. This most recent trip, I checked carefully for knives before heading to SFO. When I entered the line, they were low on bins. I started taking things out and asked if I needed to remove the Kindle and game system. The TSA agent said I could leave them in, so I did. By the time I got to the other end, I was pulled aside and questioned, as they checked for any suspicious residue on the devices. They eventually handed me the devices back and escorted me to the beginning of the line, where I had to go through all over again, this time with the Kindle and game system in a bin.