And third can someone tell how can i recognise scams in this type of commercial sellling ?
Not so difficult. Firstly, if someones like OPie here, want to sell (or buy) a big amount of BTC. These days even 1BTC is considered "big". Secondly, the use of public places as a means of security is out of the question. Being in a park with eg. $150k on you, won't save you from a possible robbery/ kidnapping/ whatever. Especially, when the thread/ ad is created by a newbie, thus a total stranger who has nothing to worry about and knows where you will be. Also, if he/ she has the BTC that he/ she claims, you can ask to sign his/ her wallet to prove ownership. Scammers will avoid it or suddenly vanish, like the OP here who deletes his Telegram username...
Finally, you have to ask yourself this: how logical is someone to sell his big amount of BTC in the middle of a park or in a train station or in a marketplace? Why choose to do this when he can do it in different (known and not so known) ways?
