Hmmm I'm in the middle , I do not like leaving any child screaming but I know if a child figures out he /she can scream and get up , I don't like either . I had a horrible napper and I did let her CIO , and she did !!
After 3 days of letting her she started laying back down and would take the required nap , of 2 hrs ( only one nap though ) I would just walk in , lay her down and walk out , non stop . I didn't want her to be afraid but couldn't handle a 16 month old with a 35 min nap all day . That was my only experience with a child who screamed instead of sleeping .