Nobody can see htaccess. Unless you have the worst host in the world, your server's config file contains a line that says something like
<FilesMatch "^\.ht">
Order Allow,Deny
Deny from all
</FilesMatch>
The condition could easily say something broader like "^\."
but .ht is conventional as it covers both htaccess and htpasswd.
You can easily test this by requesting ".htaccess" in your browser, same as you'd request robots.txt or sitemap.xml or any other file.
Matter of fact, this block is so universal that I can't remember ever meeting a malign robot even
asking for htaccess. (In my case it wouldn't help them a lot, since the IP blocks are in an extra htaccess file in my userspace, which you can't browse to.)
The crucial difference between robots.txt and htaccess is just this. Visitors can ask to see robots.txt and can then choose to follow its directives. Visitors have to obey htaccess whether they want to or not.
:: detour to check something ::
Thought so. The boilerplate config file that comes with MAMP has the built-in line
<FilesMatch "^\.ht">
Order allow,deny
Deny from all
Satisfy All
</FilesMatch>
-- and that's for a pseudo-server that would only ever be used on someone's local HD. Someone else (phranque?) can say what you get when you download the Apache software; I'm sure it isn't a blank piece of paper that you have to fill in from scratch.