[jacquesm]

> Doesn't it seem likely that the person who did this is in a better position to judge the potential consequences than you?

In fact, no. If there is a dispute and you forego the legal option you might get your ass handed to you. Things like this blow up in the face of the party doing them as often as they lead to some kind of settlement.

The damage to the client could outweigh the amount owed (assuming there is one) very rapidly.

> Unless OP is right on the threshold of being hard up for work, it makes no real difference to his dealflow, and it has a nonzero probability that it will shame somebody into paying.

It also has a non-zero probability of him/her being sued for (substantial) damages.