Paragraph on trade-offs between removing time travellers and capturing early stages of an outbreak

[hyanwong]

When setting parameters such as the retrospective window duration and the minimum group size, it appears as if there is a trade-off between weeding out time travellers, and getting early resolution of an outbreak. As time travellers can have a substantial effect on the quality of the ARG, we are tweaking settings to prioritise reducing those.

I suggest that explaining this trade-off will need a separate new paragraph (or more) in the main text.