  A four-dimensional effective theory that arises as the low-energy limit of
some extra-dimensional model is constrained by the higher dimensional Einstein
equations. Steinhardt & Wesley use this to show that accelerated expansion in
our four large dimensions can only be transient in a large class of
Kaluza-Klein models that satisfy the (higher dimensional) null energy condition
[1]. We point out that these no-go theorems are based on a rather ad-hoc
assumption on the metric, without which no strong statements can be made.
