Client says they "don't sign contracts" - should I walk away?

Sorry for the wall of text. Potential $15K project. Sent my standard services agreement. Client responded "we don't sign contracts, we just work on trust." Should I run or is this common?

Ok so update: They signed the simplified agreement. Turns out they were just intimidated by the 8-page original. 50% deposit arrived today. Crisis averted smh!