I'm pointing out that your assumption that the OP will be grateful for teachers taking her child away in a few years time is a big leap. I feel no thanks to the vile woman who watched my child being terrorised. I feel no gratitude to the Head who put pressure on us to encourage her to go. The money wasn't an issue for us but I know parents who just couldn't find the money and their children must have felt left out if they wanted to go and I know parents who went without to save the money for the trip. When my GS told us who'd just been promoted to a senior leadership role at my son's old school my son laughed and said he remembered the night when he was in year 7 and that teacher was newly qualified and slept in a drunken stupor in their dorm one night as he was too drunk to find his room. Yes I was so grateful he went on that trip.
I have no idea why a residential needs to be a 3.5 hr journey away, in what way would a residential an hour away mean they can't have all that bonding and cementing friendships? Another nightmare for one of mine was travel sickness, really bad travel sickness which wasn't helped with popping a pill or wearing a wristband. Wouldn't it be cheaper and less intimidating for some children if they knew that they were closer to home? Wouldn't it be better for the OP who could attend daily to support her children and colleagues on her working day and go home to her own child.
Two of my children experienced their first residential "camping" out in the school hall for a weekend. They did lots of games and activities, it cost the princely sum of the money for their trip to the local fish and chip shop on the Friday night and a bit of money towards foods. Every child could attend, every child was happy to attend, they all did their bonding without long journeys, expense and issues for teachers as it was easy for them to swap round over the weekend.
I know local primary and senior schools are doing their residentials abroad, the junior schools seem to go to France, Belgium or the Netherlands. Why is that necessary? The senior schools I've known of doing trips to the Amazon, Colorado, South Africa plus of course the skiing trips to France/Switzerland or wherever. Huge costs in a coastal town with lots of deprivation.
In short yes I'd be perfectly happy if residentials were stopped or controls put in place e.g maximum costs.