So what if I have an open grounded outlet?!

Three hole grounded outlets are installed though no grounding wire is present. The use of 3 hole grounded type outlets gives the impression this safety protection circuit is present, when in reality it is not. Older style two slot outlets are still available and 3 wire GFCI's can and should be installed per electricians recommendations. Three hole outlets are more convenient and are often installed without consideration to this situation.