Comment on "Can we measure structures to a precision better than the   Planck length?"[arXiv:1205.3636], by Sabine Hossenfelder
  First principles do imply a non-zero minimal distance between events in spacetime, but no positive lower bound to the precision of the measurement of a single coordinate. 
Sergio Doplicher, Gherardo Piacitelli, Luca Tomassini, Stefano Viaggiu
gr-qc hep-th quant-ph