The ultimate answer for WhiskyJim is to install a dehumidifier. His post indicated he has no moisture problem at present, just high humidity levels. I have assumed that since there is no problem before applying the drylok, the added insurance of using it as a vapor and moisture barrier is not detrimental to the objective of drying out the basement. Drylok may reduce the moisture levels by modifying moisture off the walls. I don't think the problem goes away without the dehumidifier.
The premise of whether drylok would trap moisture in the block seems faulty. Assume the absence of a drain system, the inside (or outside) basement wall is waterproofed and elevated groundwater can not go around the building. Hydrostatic pressure could build up to tremendous pressures and either the floor or wall would eventually fail. Drylok is clearly not going to make that kind of difference. In the presence of water under any head pressure, I assume drylok will fail to contain water (I have seen it do remarkable things with block moisture, but it ain't no swimmin pool). So, you are right under these condition the drylok would fail, but I don't think that was the described condition. Whiskyjim's walls are dry.