  Two simple ways to identify and explain fake Lax pairs are provided. The two
methods are complementary, one involves finding a gauge transformation which
can be used to remove the associated nonlinear system's dependent variable(s)
from a fake Lax pair. The second method shows that excess degrees of freedom
exist in fake Lax pairs. We provide several examples to illustrate both tests.
The tests proposed here can be applied to all types of Lax pairs, including
scalar or matrix linear problems associated with ordinary or partial difference
and/or differential systems.
