What are the laws against selling t-shirts at concerts?

Here is the situation:

My friends and I had the idea of selling t-shirts in front of the stadium at the upcoming Justin Bieber concert. Now, we know we are not aloud to print the Justin B logo or his image in anyway due to TM violations.

However, we were wondering if we were to print a T-shirt that says I LOVE JB, would that fall under the same laws?

Any opinions would be greatly appreciated!
The show will be in Montreal, Qc.

justin bieber concert