Pontoon boat slides are perfectly safe to use for both adults and children. You need to just cautiously place them at the right place keeping in mind the water depth.
Moreover, before using them, either you can get yourself wet or the slide so that you do not hurt yourself while using them. It is important that after inflating the slide, you need to get them a bit wet to prevent sunburn.
If you follow all the instructions, then there is nothing to worry about. Additionally, keep in mind the weight your slide can handle. In fact, boat slides make your water diving experience more fun and exhilarating.