Well I think its just a courtesy thing to let people know of that. It also probably would drive people a little nuts to see someone walk around with their shoes untied without care. It would bother me lol!

I like to just slide my shoes on and off. What I do is after I lace a new shoe (but before tying them) I take the right and left side of the top of the shoe and pull them apart as If I am trying to open up the shoe more to see something that fell in. Since the laces are untied the laces stretch out more in the loopholes and give the laces more slack. Then I take the shoe on and off and make sure it is loose enough for me to take on and off without effort. and then I make a double knot without pulling the strings tight, just leaving them as slack as they were. Then they come on and off the same as the test run I did before tying them and I never have to tie my shoe again lol. Elastic is also a solution.