I agree. We do wait a day for string installation on long runs though.Also found one should install the pull line ASAP after installing underground raceways even if not intending to pull conductors right away. Condensation or any other reason to have water in the line makes blowing a line in more difficult if you wait too long and this water has accumulated.
A few years ago, we had a 1000' run of 4" that had a measuring string installed right after conduit installation. A couple days later we went to pull the rope in and we found the measuring string was stuck, from excess glue oozing through some of the joints into the conduit.