I guess it would be a minority because telling the truth is easier and faster under most circumstances.

But yes, all these studies whose the authors authoritatively make claims but these are are based on people answering questions regarding themselves (how often do you cheat on your partner?) - I never believe these numbers.

Deception vs. honesty on certain questions in itself is a huge revealing factor in a person's personality.

Not really - these Likert question studies are so much easier to click through rapidly. You can double or triple your hourly rate depending on how bold you are. Would a college student cheat their psychology department out of 10 dollars? Maybe some.

I wonder how much shrinkage (wasted questionnaires) they have to account for? Pun semi-intended.

It's accounted for in modern psychological tests.

Edit: to clarify, there are many other questions that will seemingly be somewhat related or unrelated that will infer later on in the test if you were lying. People who aren't familiar with the tests won't notice it in an honest testing.