I also suspect that being virtually within the town (urban area) SEN is more susceptible than most to non-travellers turning up for a night in the warm/dry. This itself would be problematic. STN has joined LHR in moving on sleepers. I’m not sure what the situation is at LGW or LTN after dark.
I’m in agreement this will affect very few travellers, and I’d suggest the passengers it will affect aren’t of any value to the airport anyway because they won’t spend anything and by virtue of seeking cheapest fare available would in fact return when a £5 flight to Dublin is available.