I understand that we may not use non-commercial datasets in training for building commercial MT systems, while we can use them in the testing phase only.
What about the development/validation dataset? I see we disable gradient calculations during the validation phase, and I am not aware of any parameters tuned based on the validation score (please correct me if I am wrong), so nothing really goes to the training.
So, is it a generally acceptable behaviour to use non-commercial datasets for validation (i.e. after a number of training steps or epochs as it is handled in OpenNMT and similar toolkits)?
I would appreciate sharing your point of view. Thanks!