I run leg 5 final descent the opposite way many times in training and always make sure the gates are closed because of the livestock escaping and ending up in Waterfoot.
It doesn't take much to close a gate, maybe seconds. It's a shame this has happened and UU seem to be trying to catch us out if that's the right phrase. I'm gutted. I wish UU would put more effort into clamping down on motorbikers ripping up the Rossendale countryside.