According to
this, the US CBP staff rosters are being cut back in Shannon with the result that the late-afternoon BA flight will no longer have preclearance.
(Side note: the minister is quoted as citing an average of 18 passengers per flight. Is that accurate? Is the morning flight busier?)
If this is confirmed, what is the likely outcome? BA can't fly non-stop, at least not until the CSeries arrives
They are unlikely to be able to make a quick splash-and-dash stop in DUB - it would take longer and reduce the attractiveness of the service. Is that what they should do? Should they retime the BA3 an hour earlier (less attractive commercially) and maintain preclearance at SNN? Suspend the flight altogether?