No. Just open your folder. Take a look at the picture attached. The files of the folder are listed on the left, and the names of the people on the right. MB is me. The other person I shared the folder with "c" hasn't accessed it yet. I know this by placing my cursor on top of the "c" and the message in grey (I covered her email address to protect her privacy) appears.
I totally agree that this is a problem, I work with people around the world in many time zones, with different levels of understanding of how dropbox works and sometimes with limited internet. Not knowing if they have accessed the folder is a huge pain, as I cannot pinpoint when someone is having problems. I like dropbox a lot, but just cannot imagine why anyone would want to remove this function... Especially, it works with files! if you select a file (not a folder) you can go in the activity log and check if someone has viewed it. So this gives you some indication about the folder (if they have viewed a file in it, they have accessed the folder). But still, it does not give a garantee of access to the folder if there are not files in it yet. If we have it for files, why not for folders?