[Michael Martin]

I think it's fine as long as they are racing cleanly.
Rolling road blocks, punting other cars off etc is a no no. But if it's just a change of position between them (Bottas/Hamilton) no problem.

Biggest thing for me is not to hit my teammates. And if they are faster than me I'll let them through. But generally if someone is alot faster I'll let them through then try to follow them.