Chronology protection in a toy surface plasmon "time machine"

Recently introduced toy surface plasmon "black holes" and "wormholes" (New Journal of Physics 5, 147.1-147.8 (2003), and gr-qc/0306089) can be used to create a toy "time machine" according to a number of published designs (see for example I.D. Novikov, Sov.Phys.JETP 68, 439 (1989)). Assuming that such a toy "time machine" does not work, a general prediction can be made of strong electromagnetic field enhancement inside an arbitrarily-shaped nanohole near an arising effective event horizon, which is supposed to prevent the toy "time machine" from being operational. This general result is useful in description of the nonlinear optical behavior of random nanoholes in metal films.