Clone record displays

Our guys are accidentally deleting records because of an issue with views - it's not good!

Customised views often display a record twice within a list - it's not a duplicate, it's definitely the same record that's being showed.  So far we've found 2 reasons why:
1. In phone call views, there are more than 1 phone call record - that's fine we found a way around that
2. In customer/lead/prospect views, sometimes a clone appears because more than one address is stored on the record - this is a pain but can be avoided with housekeeping.
It still occurs though and I havent been able to work out why.  Well-meaning users are deleting these records believing them to be duplicates but of course they're not, so the whole flipping record gets removed!  Obviously this is not a good thing.