  We critically analyse and compare various recent thought experiments,
performed by Amelino-Camelia, Ng et al., Baez et al., Adler et al., and
ourselves, concerning the (thought)experimental accessibility of the Planck
scale by space-time measurements. We show that a closer inspection of the
working of the measuring devices, by taking their microscopic quantum many-body
nature in due account, leads to deeper insights concerning the extreme limits
of the precision of space-time measurements. Among other things, we show how
certain constraints like e.g. the Schwarzschild constraint can be circumvented
and that quantum fluctuations being present in the measuring devices can be
reduced by designing more intelligent measuring instruments. Consequences for
various phenomenological quantum gravity models are discussed.
