My suggestion is simple:
ask players if they experience lag problems, with a small and simple explanation of what is lag.
Poll should also include question about player's current location (US, Europe, Asia, other).

This way developers will know how many players play outside of US, what % of them (if any) experience lags and what % of US players experience lags.

What to do with it is what they will have to decide by themselves, my task is to give them numbers to think on.