If we doNOT use WSUSor local-accounts onourLaptops(which are on the domain), what specifically will happen if we haveduplicate SIDs. I haven't seen or heard of any problems. I have only read it is not supported.

Hello,Can you please eloborate your question more if you are talking about imaging laptops and using the same images without changing the SID then you will face problems after joining the laptops to the Domain, because they will have the same SID.

The scenario you described is correct. Specifically what problems can occur when you have multiple computer objects on the domain with the same SID.