El Reg reports [theregister.co.uk]
The Internet Engineering Task Force has taken the rare (and possibly costly) decision to relocate an upcoming meeting out of America.
IETF 102, scheduled for mid-2018, was booked for the San Francisco Hilton, but instead will be held in the Fairmont Hotel in Montreal.
The reason, as announced [ietf.org] by IETF Administrative Oversight Committee (IAOC) chair Leslie Daigle, is the President Donald Trump administration: American travel restrictions make attendance uncertain.
[...]travel restrictions have been bounced around between the US legal system and the White House, and the Oversight Committee hasn't seen anything to reduce that uncertainty.
[...]it is impossible to know or predict the extent of the restrictions placed on individuals attempting to attend IETF 102 twelve months from now, or the level of uncertainty that will exist, and the impact that will have on the ability for the IETF to hold a successful meeting in the United States at that time. However, the current orientation and actions of the US government provide no basis for expecting conditions at the US border to improve for non-citizens.
[...]if the IETF cannot stage something in San Francisco, it will likely lose any deposit paid to the venue.