Lease termination - landlord's discretion?

[Sam Leon]

We all have tenants breaking their leases for a variety of reasons.  Most leases spell out explicitly what happens when you break your lease.  No ambiguity there.

However, occasionally. I find myself as a landlord, depending on the reason for breaking a lease, try to give a tenant a break - by imposing a lesser penalty than stipulated in the lease IF I was given adequate notice prior AND it's something beyond anyone's control such as a job transfer or family situations etc...AND the tenant has been a good tenant all along...

So in such a case I gave "Joe" a break and didn't charge the full penalty agreed to in the lease.

Now tenant "Bill" who lives next door to "Joe" wants to break the lease and I referenced the early termination terms and clauses are all clearly stated in the lease agreement but he said "I heard that Joe didn't have to do that..."

I made an exception at my discretion to deviate from the terms for a number of reasons.

Could I get into trouble for not enforcing the terms equally?  Could someone twist this into some sort of discrimination claims?