I've talked to quite a few folks that have been unable to attend meetings in the US because of visa issues. Some consideration is needed for these reasons. Also, the delay in getting future meetings listed has just made the situation worse.
Failure to publish venue logistics details at least 18 months in advance -- as it more typical for major international events -- causes a variety of problems. However the implications of requiring locking it down that far ahead has never been deemed a requirement.
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