Employers are following the law when it comes to pension lump sums, and the law is designed to ensure they don't cheat their employees. But that doesn't seem to stop them from finding ethically dubious ways to conduct their programs.
No, you shouldn't. Your pension is protected by the PBGC.
Are employers ethically obliged to tell workers if they're leaving money on the table?
Lump sums in lieu of pensions are great - for a small segment of the population only. But there's no cheating involved in the calculations.