@kissymoose
No, it was not difficult to get a seat.
To be honest in South Africa there are not many people interested in sitting on such committees, maybe the trend is different in other countries.
I was actually asked to join after numerous emails which I sent to the publishers with regards to queries and issues I found in a specific code of practice. The emails eventually went to the champion of the committee, who later asked if I would like to join. The queries and issues were actually found to be mistakes and typos in the new edition of the code.
To be honest I think it is good for practicing engineers to sit on these committees, one of my big reasons is that there are many engineers out there who are not very competent and relay heavily on software and further more lack the basic understanding of requirements in codes and design work. To give an example I met a senior engineer (+20 years of experience) in course I attended, he complained about solving a quadratic equation stipulated in the code (for the compressive strength of an unequal angle), stating that it was too difficult to use and solve... Personally I think it pathetic, but it's the opinions of these types of people who also influence the codes and actually restrict it's growth. It is a topic that comes up in many meetings, the complaint that engineers find things to mathematical or complex to use.
Being a practicing engineer also allows you to voice the opinions of many of your colleagues and assist in growing and shaping codes. Obviously this works as a negative if you have the mentality of the gentleman I described.