In all countries around the world there currencies are all printed in paper which is called note though there maybe countries who still use coins till now. All around the world money can be misplaced maybe from your pocket, your hand or maybe your wallet may even get lost but still some people don't feel it when their money get lost because it's not that very high in exchange like in Nigeria where we have our highest currency which happens to be 1k and many other currencies like #500, #200, #100 and others most times we misplace this money and others pick it up with joy of having what you didn't work for but in this recent economy everybody has refused to lose money as usual ( laugh ).
What if the Bitcoin was in notes and with the same value as it has now, do you think anyone would misplace it or even walk with it on the street. Eventually you see a Bitcoin note will you return it to the owner. Let's be sincere and also see it as fun.
you've missed a whole lot of point in course of your writeup.
First off, Bitcoin is a decentralized digital currency and anything that makes it to be printed, it has lost that digital and decentralized nature. If bitcoin is being printed then we have to talk about how much Bitcoin is being printed into circulation and also regulate how they are being pumped so it doesn't get excess or scarce which automatically means it is no longer decentralized.
That being said, the decision to pick someone's misplaced properly on the street is a personal issue and you can't get a general opinion regarding it. Based on the kind of society we live in and looking from the religious and diabolical point of view, it's not advisable to talk up even fiat on the road because the days are evil. If it's a property like phone that you could easily reach back to the owner that misplaced it, then it's not a big deal to take it for that purpose but anything outside of that, it's a no no for me.