The legality varies by state. For instance, in California it is illegal to possess a watch without a serial number. NEVER buy a watch or anything else without a serial number.
The reason those internet dealers remove the serial numbers, is so that the watches they sell cannot be traced back to the authorized dealer they bought the watches from. Authorized dealers have contracts with Omega, and are not supposed to discount watches more than 20%. If Omega found out that a dealer sold watches at a deep discount to unauthorized agents, they can void the contract with the dealer. Buy with a serial number, then there is never any question that the watch is legitimate, or that the watch is yours.
: Looking again for another Omega, the place on
: the internet I usually deal with leaves the
: serial # intact but there are a lot of other
: places that are cheaper but remove the
: serial #. Is it legal for them to do this, I
: know I would not buy a car without a VIN #
: or a TV without a serial #. How do you know
: the watch is legit (not stolen, etc). Some
: dealers give a letter of authenticity with
: it for insurance purpases & others say
: take it to your jeweler to check. I do not
: want to spend $1000+ to have it opened for
: no reason. Again is it legal for them to
: remove the #'s.