If you are familiar with gardening, you know why. There may be tiny plants just beginning to sprout, and your clumsy feet will crush them. Also, your weight can crush loosely-packed garden soil, or your clumsy feet can kick the watering heads. Stay out!
I am happy to have people visit The Tropical Paradise, but I watch with horror when they stroll up into the garden, killing plants and kicking watering heads and misters, which I have to go repair later on. I have excellent garden paths, made from flagstone, set in solidly and grouted. If you have people who are *walking on the dining room table* in your garden, it's probably because you have not designed a logical path for them to stay on. Make that part of you gardening project. People will want to see your garden. And they will need a place for their feet!
Please don't walk into my garden - unless you are a wiener dog!