  Gravitational-wave (GW) observations provide a wealth of information on the
nature and properties of black holes. Among these, tidal Love numbers or the
multipole moments of the inspiralling and final objects are key to a number of
constraints. Here, we consider these observations in the context of
higher-dimensional scenarios, with flat large extra dimensions. We show that --
as might be anticipated, but not always appreciated in the literature --
physically motivated set-ups are unconstrained by gravitational-wave data.
Dynamical processes that do not excite the Kaluza-Klein (KK) modes lead to a
signal identical to that in four-dimensional general relativity in vacuum . In
addition, any possible excitation of the KK modes is highly suppressed relative
to the dominant quadrupolar term; given existing constraints on the extra
dimensions and the masses of the objects seen in gravitational-wave
observations, KK modes appear at post-Newtonian order $\sim 10^{11}$. Finally,
we re-compute the tidal Love numbers of spherical black holes in higher
dimensions. We confirm that these are different from zero, but comparing with
previous computations we find a different magnitude and sign.
