congestion buster

My local shopping centre (Basingstoke, UK) is mainly linear in design and a favourite meeting place, by accident or design, is outside Marks & Spencer in the centre of the 'long drag'. Large groups of people form here to chat, blocking the way completely, many with pushchairs (US: strollers?) and shopping trolleys (US: don't know whether you have them: wheeled boxes for people, mainly elderly, to transport shopping). On Saturdays it's the worst, which does cause me to wonder why the retired in particular (also non-working parents) choose that day to head for town. Trying to pass these groups is difficult and can attract hostility from those who believe it is their right to block the way.

My ideas is a robotic wheeled device which follows a pre-determined continuous loop through the shopping centre, following a buried cable or white line (the former being less susceptible to jokers with white paint!). The device features flashing lights and warning tones, and basically breaks up these clumps of people to allow those who want to move aound the shopping centre to do so. If people want to stand and chat they will learn to do it in the corners where the robots don't go - and they are not in the way. The robots move at a resonable pace (3mph), allowing them to cover plenty of ground and meaning that following a robot is guaranteed to be a fast way to get around.

The robot comes in three modes:

1. Gentle: rubber bumpers, and it stops if it hits anyone.

2. Assertive: wooden bumbers, and it slows down if it hits anyone.

3. Aggressive: whirling knives and it keeps going regardless.

Probably needs an emergency stop switch, but that's covered by a camera and there's a £50 fine for pressing it without cause.