Do you think “Speed Traps” should be illegal everywhere?

I was watching a YouTube account about an interabled Couple and I don’t know how long ago this video was but they were telling a story about how they got pulled over when they were on their road trip. They stated that they were coming off a highway that was 70 mph into a little small town that went to 35 mph and it was within a minute from going 70 mph to 35 mph and right beside the 35 mph sign a cop was there so they got pulled over. This is definitely a speed trap and they can be everywhere. I have a few in my county because we have several different highways and some of them go into a little town so you’re going from 65 mph all the way down to 25 mph and if you’re not from around here then you’re not going to know because there are no signs saying you need to slow down and that it’s going to change to a certain lower limit. So you legit are on the highway and then within a minute of the highway ending there is a sign that will say 25 mph. I feel that speed traps should be illegal and cops should not be able to pull you over for it unless you’re not slowing down and you’re still going over the speed limit after passing the sign already and I also feel like they should put up warning signs that you are going to have to slow down very soon. I feel like they should tell you a mile or two before you hit that speed limit sign. It’s only from being on a highway to entering a small town because other highways that we have sometimes lead to a toll and it will have a sign up with an arrow above it saying a speed limit because it is warning you that you need to slow down soon and it will have about three or four of those warning speed limit signs but it’s only the highways that go into a toll but other highways that go into to a small town, there’s no warning at all and a lot of people get pulled over every single day for it especially if they have not been on those highways before. So do you think it should be illegal as well?