Yes, according to the recent reports in the early 2000's around 90 times speed skaters - not known how many different skaters, but 5 or 6 of them Dutch - were 'warned' by the ISU, by sending a doping control officer to the skater when they had 'bad' blood values. Blood values couldn't result in a ban, so sending a DCO was a way of saying "hey, stop and take care" and magically, the blood values went down immediately after the DCO visit.
This all is mostly based on the words of Harm Kuipers, former member of ISU's medical commission, by the way.