I was the editor for a randomized trial submission to our journal which had a total sample size of 132. The authors used simple randomization (i.e. no restricted randomization, such as blocking or minimization), and they ended up with 58 in one group and 74 in the other. This is pretty clearly a moderate imbalance, and not really desirable in a clinical trial.
The question I had was: how probable was it that this result was due to chance alone? Could there have been another explanation for this disparity, such as a faulty randomization generation algorithm? I satisfied myself that the group size disparity would be acceptable if the probability that it could have occurred by chance alone was > 5% (the typical value used for statistical significance).