Message parents

[Thoralf-M]

In https://github.com/iotaledger/IOTA-2.0-Research-Specifications/blob/main/4.1%20The%20Tangle.md it says
Each message has a possible number of parents from 2 to 8 with repetitions (with 2 as a default value), where at least one is a strong parent. Does it mean that if there is only one tip available it should be provided twice in the message and only one time as strong parent? Why allow repetitions? Seems like a waste of space