Have almost been tripped up on these a number of times, mainly because they seem to extend to about 3ft behind someone, which seems really inconsiderate, especially in confined spaces like the tube. Also, most of these bags on wheels seem to be no bigger than my handbag. Can people really not carry their own bags and use up less space? Understand for suitcases etc or for people who aren't able to shoulder a load but not for teeny tiny bags belonging to able bodied adults.