I hesitate to point this out but the RSPB wants Herring gulls (as seen at the seaside and on rubish tips) to be put on it's red endangered species list. I believe currently it's on the amber list.
BBC NEWS | Magazine | The awk, awk, awk-ward squad
If that were to happen "local authorities would be required to draw up a 'Biodiversity Action Plan' to protect gulls". In which case landing and ingesting a few, when you could divert, might cause a spot of bother.