Gataloca- the reason to do it is that rubella vaccination rates are falling in certain countries (eg UK) due to scaremongering over the MMR (Mumps, measles, rubella) vaccination. I agree with you that the chances of contracting it are small, but mass immunisation only works if pretty much everyone gets vaccinated. Incidence of rubella fell because immunisation was so popular.

Now there's a risk that if there was an outbreak, it wouldnt be as well contained, so for women TTC, who cant remember having the vacc as a child/ teenager, it's worth checking immunity status.