Of course you can spot them with the 1st message. I only use WhatsApp with SB's that ask me to use the app, so any unsolicited message I get is scammy.
I like to answer the first few messages as though I am the intended recipient. I never claim to be the named person, I just give answers that are a reasonable-looking reply.
Scammer: "Dan, did you have time to review the quotes for the project?"
Me: "I did! I think they need a lot of work before presentation. Frankly I'm pretty disappointed in you."
Whatever the reply I just go with it and keep moving the conversation along. Great fun! When the scammer finally decides to set the crypto trap, I shut them down with one simple sentence:
Me: "I don't believe in trading commodities, especially those based on fantasy valuations."
That usually brings silence.
Other tactics: I go deep into romance mode. Asking for pics, then more pics after I proclaim "her" beauty. Then I ask questions about her life, parents, past sexual experiences and promises to "rock here world" when we finally get together. Throughout all of this I repeatedly ask her to meet me for dinner. I explain that a face to face date is critical to build trust and affection. Ultimately, I offer to send her my "best dick pic" with the promise she won't share it with anyone, because that would ruin me. After I get her to promise multiple times, I send her a pic of Trump.
Eventually they realize I am a colossal time-waster. Mission accomplished.
Life is good
The Cat