I didn't promise you...

We struggle with attendance at our drop out recovery program. Most of the students I enroll are full of enthusiasm and profess an undying commitment to completing their graduation requirements. Too often, many lose their momentum. So I thought having them sign a contract would help them stay focused. As each student signs, I remind them that they are committing to attending a minimum of 20 hours per week.
I understand losing steam after months of hard work, but we haven't even completed our 1st week!
I pull in "Lee" who has been absent 2 of the 4 days we've been in session. I inquire about his absences and remind him of his promise to attend.
"I never PROMISED you I would attend."
"You didn't? You signed a contract."
"Yeah, I signed that contract, but I didn't PROMISE you."
"What do you think a contract is?"
"I don't know, but I didn't PROMISE."

Tomorrow I'm shredding all my contracts and making my students sign promises.