Here's a travel video entitled Disabled Guide to Guell Park in Barcelona that illustrates a common issue in access and travel situations - poorly marked trails.
You'll see that the disabled traveler proceeds a long way up a trail only to find two steps. There is an alternative way to go that's accessible - but none of this was marked to avoid having this happen.
Happens all the time. You're sitting there in your mobility device thinking "If only this had been marked..."