It's true even if you are fully verified. I'm verified and have a weekly sell limit, which is less than what I have on balance.
My limit is by week and is less than $10,000. So a default may be meaningless. And it's most certainly not a daily limit. I have to believe that the limit is based on your personal activity, how much you have on deposit, the size of transactions you've made, whether you buy with a bank account or credit card.
What's most important is that if you go to Coinbase and click on "sell" you'll see your limits. They make it very clear, what your total limit is and what your progress toward that limit may be fore the week.