I had to look this one up as well. The relationships rewards needs the following:

Eligibility*

• Checking account with direct deposit & $45,000 or more in combined loan and deposit balances
  
• Checking account with direct deposit & 45 or more monthly combined debit and credit card transactions
  
• Young adults (ages 14 - 23 years old) automatically qualify
  

Makes it less attractive for most but could be worth jumping some hoops for 3%. I have also not yet read that far yet to see if getting true cash back takes a hit on the 3% or not when it comes to redeeming.

EDIT:
This one looks to be misrepresenting the cash back. It is a base of 1.5% Cash Back. If you meet the eligibility criteria above they show that you get a "0.50%" bonus. In that case you are getting 2.25% Cash Back - NOT 3%. In a promo video, they talk about "additional cash back rebates on credit union products and services." So they only way you are getting the full 3% is by buying their stuff. Not cool.