It's really just not a good solution. It's more complex, it's way slower, it shows they're not familiar with stuff they really should be familiar with.

Anyone who struggles to write a function to determine evenness of a number, and has to throw in some crazy solution to be able to make it across the finish line, is going to really struggle with real production code. They're going to produce stuff that's going to make everyone's job a lot more difficult.

return (x % 2) == 0;
return (x & 1) == 0;
return (x / 2 * 2) == x;
return x/2 == (x+1) / 2;

You can come up with unusual solutions and it can be fine. You can't come up with cockamamie solutions, that's why you're doing the test.