Good Morning K.,
I am currently having the same problem with my son, he is now almost 23 months old. I have thought of using the same time of tape too, in hopes of keeping his diaper on, but if your son can remove it I know mine would too!
When this first started, I changed the brand of diapers that we were using, from Pampers to Huggies overnite protection. I have used all the different brands of Huggies but the overnite diapers are the most difficult from him to remove. The taped portion of the diapers / straps were harder for him to remove, so it took a little longer, by that time we were able to catch him in the act. That only worked for so long, before he found another way into his diaper. In most situations, someone might think so what, he got into his diaper. But when it is an all day, everyday event it is a problem. So now we are in the process of trying to potty train my son along with having him wear onesies with shorts or pants over them. This makes it difficult for him to get to his diaper. So if you come across any better ideas please forward them too me, I would greatly appreciate it.
Mom of three active and wonderful children ages 10 years, 5 1/2 years and almost 23 months with one more on the way!