My opinion of this paper is completely biased by the fact that I’ve actually met David Kipping and that I read this paper back when it first went on the arxiv. This was my first exposure to SETI (beyond science fiction, if that counts) and I think it went well!
Kipping and Teachey postulate that a civilization (even the Earth) could use lasers in some interesting ways. They first suggest that a planet’s transit could be clocked, monochromatically, against a Kepler-like survey, without the need for much power (~30MW). Due to the Earth’s rotation, this would require multiple laser stations, but in the end, it would be doable. They then continue on to talk about clocking the signal at all wavelengths. This would be a bit more challenging, since many lasers at many different lasers would be required, and again these lasers would need to be placed around the planet, and the power requirement would increase by an order of magnitude, but a committed civilization could manage it. Both of these cloaking processes can be argued against since the planet would still be detectable via other detection methods (namely RV).
The last bit of cloaking they suggest involves the cloaking of biosignatures. A disequilibrium in an atmosphere (normally of oxygen) is a decent indication of life on a planet. These and other related absorption features are referred to as biosignatures. If lasers were emitted at these absorption features, then the planet would still be detected and noticed, but it would just not be studied much since it would be presumed uninhabitable. This is all, of course, under the assumption that other life out there is Earth-like, and that this Earth-like life would be looking for signatures similar to their life (Earth-like). Because of this Earth-like assumption, it is possibly that another civilization is already doing this for *their* biosignatures, we just don’t notice it though because we are looking for our biosignatures (also clouds are apparently all that we can see right now).
Lastly, the authors bring up the point that this laser method can be used not just to cloak, but also to signal existence. They briefly mention that the easiest way to get someone’s attention with this would be to cloak the transit’s ingress and egress, making the transit appear boxy and all around wrong.
Although this is a neat idea, it seems a little far fetched and specific to me. Sure, we have tons of data, so someone might as well look through for boxy transits (I think someone has already done this with Kepler data), but this seems so absurdly unlikely to happen. However, my thoughts on the likelihood of this completely come from the way I view humanity and our goals and motivations, so it’s just as possible that my thoughts of this being a waste are a minority in the galaxy.