  A recent letter published in the journal Nature reports observation at the
relativistic heavy ion collider (RHIC) of quark-gluon plasma (QGP) formation in
small asymmetric collision systems denoted as $p$-Au, $d$-Au and $^3$He-Au. The
claimed phenomenon, described as `short-lived QGP droplets,' is inferred from a
combination of Glauber Monte Carlo simulations, measurement of two azimuth
Fourier amplitudes $v_2$ and $v_3$ and hydro theory calculations. While that
claim follows a trend in recent years to report `signals' conventionally
attributed to QGP as appearing also in smaller collision systems, the new
result remains surprising in the context of expectations before first RHIC
operation that small systems, e.g. $d$-Au collisions, would provide control
experiments in which a QGP was unlikely to appear. An alternative
interpretation of the recent RHIC result is that small-system control
experiments do convey an important message: The `signals' conventionally
attributed to QGP formation in larger A-A collisions do not actually represent
that phenomenon in any system. The present study reviews a broad array of
experimental evidence for or against QGP formation in several collision
systems. It examines in particular hydro theory descriptions of spectra and
correlations usually interpreted to support QGP formation. Available evidence
suggests that data features conventionally attributed to QGP formation
represent either minimum-bias jet production or a nonjet azimuth quadrupole
with properties inconsistent with a hydro hypothesis.
