I guess this is worth an explanation: in many European intra-city subways/trams, you're supposed to buy a ticket and then insert it into a "validator" machine that stamps current time. The validator is around where ticket gates would be, but much fewer in numbers, installed on random locations or on railings. Being on a train without the stamped ticket is equivalent to jumping a fence.

A lot of European folks seem to have positive experiences with the validator system as something convenient, less intrusive and high bandwidth, overall superior, but personally I doubt it scales out to scale and transit models of places like Shinjuku. Most rides in Tokyo commuter rails are point to point and Japanese commuters go through gate like a marching army, so it means temporary riders has to disrupt the march to get to the validator, and also a single validator in the middle of the gate area isn't going to meet demands but increasing the number of the machines kills the benefits.

btw: JRE is actually doing experiments with more modernized touch-free gates, one based on facial recognition a la Minority Report, and another based on UWB radio gadget added to phones. It is speculated that UWB is likely the intended path forward.