> all they had to pay was $5k.

They still risk being disbarred (not just hypothetically, it might actually happen) + taking a massive hit to the reputation (their own + the firm). The latter one alone is a strong punishment, given how widely-publicized this incident was in the media. It cost the firm a lot of potential clients, and the lawyer might struggle with finding a decent position after the fact (given how much more reputation-based the legal field seems to be compared to something like engineering).