A recent visit to a medical clinic found an excellent design.

The soap dispensers, paper towel dispensers, and water faucets in the rest room were "ultrasonic." When your "hands" approached closely enough to the device, dispensing was turned on automatically.

Unfortunately, the soap dispenser was so over-sensitive that it was impossible to get past it, to get to the sink/faucets, without receiving a squirt of soap on your shoulder/sleeve.

(I'll concede the point that faucets and other "points of contact" with dirty hands probably are likely to have some contamination, but these things were a little too "touch free" IMO.)

John