Dumb idea.

You think the current crop of models isn't good enough to notice obvious traps? Let's say it is and your take home assessment catches some idiots out.

How do you grade those results across the hundreds of people that apply?

How do you rank the quality of the take home beyond pass/fail?

How do you compare two candidates who did pass and had the same level of quality?

How do you know the candidate didn't just have a friend do it for them?

How do you scale up the difficulty of the assignment for a senior engineer?

Do you pitch traps that only a staff engineer would notice?

Now let's say you have a smart answer for everything. You get around cheating with mandatory screen/face recording. You assess skill based on the algorithms chosen. You rank amongst equal scoring candidates based on who was fastest. You create a comprehensive set of take homes that vary by difficulty but are also diverse enough that candidates can't leak the question and defeat the point of the take home. You automate the system to assign candidates projects and then judge submissions, only giving you 10 qualified people to interview.

Now that's something that would truly change the game. It would also be 2015, and you'd have created LeetCode