Agree. That's why almost every time I use either internal or external pullups. But IMHO that picture is too aggressive, we aren't talking about nuclear plants or any kinda mission-critical devices, within any hobbystic or home application it's not such a thing to be pointed out.
I learned a new word today 
- There is a potential the 5v power supply can short to GND, yellow traces; 20 feet of +5v is dangling out there.
- Blue trace is recommended, R1 can be the internal pull-up resistor.
-
let’s say we have circuit S1.
Let’s say the switch is 10 feet from the Arduino.
This means we are taking the +5v supply line out 10 feet and 10 feet back.
5v is now extended 20 feet with the potential of it coming in contact with things that can go pop if there was ever a short circuit on the cable.
Also, sending 5v out on a 20 foot wire allows inductive coupling to noise sources that can cause serious problems back at the Arduino. -
If we are using S2, the R1 pull-up is back at the Arduino, the switch is 10 feet away as before.
If there was a short on the 10 feet of wire, the external pull-up (R1) limits the short circuit current.
Not possible.
Either (1) 12 switches or (2) 11 switches... 22-32 or(3) 11 switches... 23-33.
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