I see a lot of people here saying "I would never do that" but I know so many people that do
It is dangerous, but sometimes there
is no other way - not everywhere caters for buggies/wheelchairs. Like here the shops etc are so tight that you sometimes have to use the escalator, because they don't have space for a lift. Probably hard to imagine, because in the UK you have lifts everywhere. But also, it's like going down the steps, and TBH if you take the escalator, you should take as many safety precautions as possible, i.e. double checking LO is fully belted in etc.
I do it when I need to, but because it's hilly here, I bought a little wrist link from Mothercare, attached it to my buggy handles. I got the idea from the Bugaboo, which come with them.
I put it around my wrist whenever I go down a steep hill (I've slipped over in the past and couldn't live with myself if I fell, let go of the buggy and LO went into oncoming traffic
I also use it on escalators, and hold onto the handrail for dear life. I also make sure I go whichever way doesn't mean I'm tipping LO upside down (e.g. I don't put the buggy front first going up the escalator, because she ends up feet above head); I don't want her throwing up all over the place.
The wrist link isn't foolproof, but it's better than not using one.