I know We had it in the kitchen at our old house and it obviously had a coating/finish on it but it still started to swell on the joints in places so I just assumed that it wasn't sealed.
If you have been using an ordinary "wet" mop to wipe your laminate floors clean then a steam mop should not do any harm as the amount of water used, compared to a mop, is minimal.
Yes but would the heat be the issue Frank? I don't mop my floors using steaming hot water......in fact my laminate often gets those large Pledge floor wipes, as they give a nice shine. Hard work on your hands and knees though
Most laminate is already sealed, and provided it's been installed correctly the steam cleaner shouldn't be a problem at all. My SIL has been using hers for about 2 years now and not had any problems