Although I totally understand this sentiment and I do reserve bulkhead seats (1A on the 787 as an example with a bassinet) and row 16 or 31 depending upon the plane United is very clear that seat assignments can be changed and often are. I have lost my assigned seating to air marshalls. I have had people moved from next to me to accommodate the bassinets (for the bassinets that affix to the wall). So United does and will move folks.

What annoys me about this is that I think United could do a much better job of when someone books an infant it should be flagged in the system so the bulkhead bassinet is available for the pax reserving the seat..

BE is very annoying to pax who book traveling with children and seats are not together. I would think UA IT should be able to flag and link so the seat to the last two rows of the airplane. Single BE pax would still get their middle seats.

For the pax with an infant BE should not be an option, again something UA IT should be able to fix.

I now when I first flew international with my 4 month old child I called before booking to understand what I needed to do to ensure a bassinet was available for the flight. However, I did this because I wanted to have a bassinet for the flight. I did not try and wing it but planned.