I did once check a written log against the online one, and it was more hassle than it’s worth. The names were not written on the paper log in the same order as the online ones, and cross-checking was laborious and time-consuming. In the process I made a mistake and deleted a perfectly valid online log. I soon received an email from the irate cacher about this. Of course, I apologised profusely and invited the cacher to relog their find, but I think they had the huff by this point and never did. Since then, I haven’t bothered.