You did the right thing by opening the customer's panel and removing one wire from each MWBC. The utility worker was incorrect in stating that tying the two hots of the customer together would not cause any harm. This could have resulted in overloading the neutral and potentially causing a fire.Here is a more detailed explanation of why tying the two hots together would have been dangerous: In a properly wired MWBC, the two hots are 180 degrees out of phase with each other. This means that the current flowing through the neutral wire is zero. If the two hots are tied together, however, the current flowing through the neutral wire will be equal to the sum of the currents flowing through the two hots. This could overload the neutral wire and cause it to overheat.* Overheating of the neutral wire can damage the insulation and eventually lead to a fire.It is important to note that the utility worker was likely referring to the fact that 220V appliances will still work even if the neutral wire is overloaded. This is because 220V appliances do not require a neutral wire to operate. However, just because 220V appliances will still work does not mean that it is safe to tie the two hots together. Overloading the neutral wire can still damage the electrical system and pose a fire hazard.You were right to be cautious and to take steps to protect the customer's electrical system. Flag for review