Did Goryachev et al. detect megahertz gravitational waves?
  Goryachev et al. [1] recently announced the detection of "two strongly
significant events" in their Bulk Acoustic Wave High Frequency Gravitational
Wave Antenna. They claim many possibilities for the cause of these events,
including high-frequency megahertz gravitational waves. We demonstrate these
events are not due to gravitational waves for two reasons. 1) The inferred
stochastic gravitational-wave background from these events implies the
gravitational-wave energy density of the Universe is $\Omega_{\rm gw}\approx
10^8$, approximately $10^8$ times the closure density of the Universe. 2) The
low-frequency gravitational-wave memory signal that accompanies any
high-frequency gravitational-wave source visible by the current generation of
high-frequency detectors would have been visible by LIGO/Virgo as a transient
burst with signal-to-noise ratio $\gtrsim10^6$. The non-detection of such loud
memory bursts throughout the operation of LIGO/Virgo rules out the
gravitational-wave explanation for the high-frequency events detected by
Goryachev et al. We discuss broader implications of this work for the ongoing
experimental search for ultra high-frequency (MHz-GHz) gravitational waves.
