Trouble is, with spam PMs like the one above, is that it's not a "time on the hands" thing. 99.9% of the time they're an opening for a scam. That's why they always request contact via their private email: they want YOUR personal email address so they can try and scam you outside of the site, or use your address for any number of nasty purposes. The really sad thing is that there are people naive enough to give that info to them. They figure oh gosh, there are no evil scoundrels on a perfectly legitimate site like ___, right? Wrong.
Helping good folk avoid the trap is why forums like RS provide safe messaging: so that you can communicate with community members without ever having to reveal sensitive, personal information, like your email address, to a stranger.
So if you get another odd PM from anyone* - especially a new joiner - requesting a response via their personal email, do NOT respond in any way; report them immediately.
The one exception (starred *) would be exchanging some private info with regular posters you've come to know well over a long period of time.