Honestly, the sensu bean to cell is probably the most defensible punt made in DBZ. Because it was returning the favor to cell after he got his perfect form and decided to not kill everyone (even though it was well, well within his power to do so) but give everyone a chance to power up and fight him 1 on 1. The sensu bean was cell's one.

Also Goku was sure Gohan had that one, bean or no. Which he ultimately did have, the only reason it got close is because Gohan out of no where started to channel his inner goku.

It wasn't a good idea at any level, but it's definitely understandable why Goku, a notoriously lenient fighter with a lot of pride and honor, to do it for him. It definitely wasn't as egregious a punt as a) letting cell get his perfect form, b) gohan not killing cell when he had the chance the first time, c) krillin not destroying 18, d) 18 not running when vegeta was busy decimating imperfect cell.

Goku's many, many punts in the buu arc however.....