LIGO is sensitive to binary NS (and NS stellar-BH mergers) too. Binary NS mergers throw off a lot of radiation, even or especially if the result of the merger

LIGO is sensitive to binary NS (and NS stellar-BH mergers) too. Binary NS mergers throw off a lot of radiation, even or especially if the result of the merger is a black hole. In the case of GW170817/GRB170817a, the evidence leads to the conclusion that there was one event and that it was almost certainly a binary NS merger. Because gravitational waves' amplitudes fall off linearly with distance rather than quadratically, because gravitational waves are so weakly interacting that they essentially do not scatter and are not absorbed, and because the environments around binary mergers (and between the binaries and us) can strongly absorb or scatter light (incl. radio and gamma), there should be lots of detections which have obscure, dim, or even undetectable optical (also incl. radio and gamma) signals. Distinguishing among the similar inspiral chirps for similar binary masses where the composition of the masses differ is an area of active research. The strong equivalence principle drives the GW similarity, but whereas binary NSes's surfaces can contact, BH surfaces (if they exist) are deep inside their horizons, so (ignoring any matter in the neighbourhood, such as colliding accretion disks) all we get from binary BH mergers is the ringdown as the hair from the lumpy merging horizon falls off leaving a much more symmetrical horizon. A mixed binary can shred the NS, leaving behind a brilliant structure. For binary NS mergers the GW events are brief compared to optical events (and the non-gravtiational radiation can interact with (relatively) nearby gas and dust as light echos and the like, so the results of those emissions can be studied for longer). It is much more likely that a GW detection will spur a search by non-gravitational observatories than the reverse. In any case, everything is carefully timestamped, and the records can be compared well after that, including by people who aren't experimentalists. :D