Yes! You can watch their status if they have opened the itinerary email and/or download the Trip Plans app. You can see this in a few places:
In the People section of the Trip View
Under the Send button within the Itinerary builder
The Trip View
1. Click on the Trip
Click on the Trip that has the shared Itinerary/Proposal.
2. Click on People
The People tab allows you to add and remove travelers from the itinerary, send invites, and manage collaborators.
The images that appear to the right of their name indicate how they've viewed the itinerary. If you hover your mouse over the icon, it will also tell you!
The Send Button
1. Go into the itinerary
Go into the itinerary as though you were going to make changes to it.
2. Click on Send
Click on the Send button in the top right corner of the itinerary!
3. Hover on the icons
A small menu will appear showing those who have been invited to the itinerary. If you hover your mouse over the icons to the right of their name, it will display how they've viewed the itinerary.
The People Section
1. Go into the itinerary
Go into the itinerary as though you were going to make changes to it.
2. Click on ...More
The button will be in the top-left corner of the itinerary, to the right of Settings.
3. Click on People
Clicking on People will open a menu that will list all the users on the itinerary or proposal, as well as how they've viewed it!