My basement being so cool in summer and cold as heck in winter (43f) (and i sit down here two hours every night) i think that the humidity would not be good. Nice tight fitting lids for me...
Yeah, in many houses the humidity could be a problem. But in here we build proper houses! x)
Well, really, the humidity is actually really good for my husband. He has asthma and cancer and various skin problems and allergies, so the moist air in our apartment makes it easier for him to breathe. And I like it, too. And, usually during the winter time the air inside the houses get reaally dry, so this is a big help.
In our other tank we do have a full lid on, and it's going to stay that way.