This, ironically, would be lying to your kids. There are very few (if any) pathological truth-tellers and you are likely not one of them. Any health adult would intentionally lies in certain situations and would be considered foolish/dumb if they didn't.

Your kids will inevitably catch you lying and their understanding of "lying is bad" would become "lying is bad if you get caught" and "You're allowed to be outraged when catching others' lies".

Teaching your kids how and when to lie, now that's a very tricky thing that I don't have a grip on.