  Flow signatures in experimental data from relativistic ion collisions are
usually interpreted as a fingerprint of the presence of a hydrodynamic phase
during the evolution of these systems. In this work, flow signatures arising
from event-by-event viscous hydrodynamics are compared to those arising from
event-by-event non-interacting particle dynamics (free-streaming), both
followed by a late-stage hadronic cascade, in d+Au, 3He+Au at sqrt(s)=200 GeV
and p+Pb collisions at sqrt(s)=5 TeV, respectively. For comparison, also Pb+Pb
collisions at sqrt(s)=2.76 TeV are simulated. It is found that non-hydrodynamic
evolution can give rise to equal or larger radial flow than hydrodynamics with
eta/s=0.08 in all simulated collision systems. In light-on-heavy-ion
collisions, free-streaming gives rise to triangular and quadrupolar flow
comparable to or larger than that from hydrodynamics, but it generally leads to
considerably smaller elliptic flow. As expected, free-streaming leads to
considerably less elliptic, triangular and quadrupolar flow than hydrodynamics
in nucleus-nucleus collisions, such as event-by-event Pb+Pb collisions at
sqrt(s)=2.76 TeV.
