Unless they will agree to paint the house red, do not hire them.
I don't want to bother you for a ride to Boston, unless you'll be driving there anyway.
I don't understand why both subordinate clauses are future. I thought that it was not possible to use "will" with "unless".
It sounds better to me to say:
I won't bother you for a ride to Boston, unless you drive / are driving there anyway.
Unless they agree to paint the house red, do not hire them.
Why is the future tense used in the examples at the top? Is it because the two main clauses are present and do not relate to the future, so if it wasn't phrased like that, we might think these sentences take place in the present (which is not true)?