It depends on many things:
Your email client/program
Your email provider
Sender's email provider
Intermediary provider/email forwarder
Method used to block - including spam blocker
By "intermediary provider/email forwarder", I mean something like GMail. For example, I use my gmail address the most. But I have it set up so it forwards all my email to my ISP's email address, which then is pulled down to my computer by my email client, MS Outlook. Plus I have MailWasher Pro in the middle checking for spam.
I can configure a rule so GMail dumps all email from a specific address into a spam folder. It will then not get forwarded to me, and the sender will not know if I got it or not.
I can also configure my spam blocker, MailWasher Pro, to automatically delete their mail too - and they will never know.
I guess I should add that I am talking about email over the Internet. If you are on a corporate network, and the email is from another person on the same corporate network, they will get a failed to deliver notice.