No, or course not. Children at that age have very unpredictable bladders and urges. Just gently remind her every hour or so to use the bathroom, and make sure she does. She is likely hiding her wet panties because she gets in trouble or feels shame over wetting herself. If she has an accident, just be casual and say, - oops, let's get some fresh pants for you. That way she will be comfortable admitting to you that she made a mistake.
At this age it is our responsibility to remind them, or walk them to the toilet at appropriate intervals. I applaud your decision not to spank. We did not spank our children and they turned in to lovely adults.
Also use those night time pull ups for kids that age. That way if there is an accident, you don't have to change the bed. My granddaughter used them until she was about 5, then outgrew the need.