A comment elsewhere here links to a color comparison. Looking at them, I doubt I could tell you which one is T-Mobile and which is Lemonade with confidence greater than chance.
Oh, I could immediately recognize which one was T-Mobile when I looked at the comparison. T-Mobile has a subdued magenta, whereas Lemonade uses bright hot pink. You can see the stark difference on their websites as well (though when you hover over one of the Lemonade buttons, it looks practically identical to the T-Mobile magenta).
I believe both of you :) Human color perception is weird like that.