Kimberly.
ArcPad employs a "Last edit in wins" rule.
ArcPad and ArcMap know what the status is for each feature in the database. Features can be new, modified, deleted, etc. When you then check your edits in, the status will change to "Processed".
If your field crews are only obtaining NEW data and aren't modifying existing data, then it does not matter in which order they get checked in. It's all new and unique so it all gets saved back to the geodatabase it came from.
However, if your field crew are modifying existing features, and two workers end up modifying the same feature, the last edit which you check in will be shown for that particular feature and the other data for that feature will be lost.
Hope that makes sense.