Logging in to open WiFi networks can be frustrating. Your device is supposed to immediately take you to the login page as soon as you try to load any new page, sometimes it does not.
It seems that the reason it doesn't redirect you is if your browser is trying to load a secure website. Secure websites are ones that have "https" in the front of the URL and not just "http". More and more websites are switching to use SSL and making themselves secure. When you go to an SSL site your traffic is protected from the router and the router can't see that you need to be redirected to the login page.
In order to be redirected you need to find a non-SSL, insecure website to go to. One that will always work is neverSSL.com. Bookmark it!
If the above link doesn't work, here is a list of links for individual websites.
Marriott WiFi: http://internet-upgrade.marriott.com
Do you know one that's not on my list? Comment below and I'll add it with credit to you!