Entanglement polytopes have been recently proposed as the way of witnessing
the SLOCC multipartite entanglement classes using single particle information.
We present first asymptotic results concerning feasibility of this approach for
large number of qubits. In particular we show that entanglement polytopes of
L-qubit system accumulate in the distance 2L1 from the
point corresponding to the maximally mixed reduced one-qubit density matrices.
This implies existence of a possibly large region where many entanglement
polytopes overlap, i.e where the witnessing power of entanglement polytopes is
weak. Moreover, the witnessing power cannot be strengthened by any entanglement
distillation protocol as for large L the required purity is above current
capability.Comment: 5 pages, 4 figure