The pitfalls inherent in using and placing absolute trust in garmmar and spell-checkers ensure that the skills of proof-readers are yet in great demand.
The best I've come across so far are:
a 'plane' in Spain
the calling of wedding 'bands'
Marshall - as a military rank
a sliver handled pistol
Shoffer was arrived - mmmmm Shoffer had arrived
Regency Romance
Raves 'n Rants