Please can you tell me how I can verify whether my details have been leaked?

I've recently purchased a domain from namecheap, with whoisguard, and if I recall correctly I didn't have to turn it on. I whois'd myself and found that it didn't leak anything. It didn't occur to me that scrapers can get at the info before you protect it.

Perhaps this has changed since your experience? Please could anybody else verify one way or another?

Cheers