The detection of GW170817 is the nail in the coffin here. A gravitational wave corroborated by numerous other teams and instruments detecting the same event using completely different physical principles. There is almost zero likelihood of such a coincidence.
Yes, in this case the theoretical models predict a gravitational wave to coincide with the observations from other trusted instruments. There may be systematic issues with LIGO's analysis, but it would appear that LIGO also reliably detects astronomical events which suggests that it does actually detect the waves themselves and not just coincidental artifacts in the analysis.
