You have to consider the age always. At 2 the ability to predict what will happen next is pretty limited. Repetition of behaviors, even ones with unpleasant outcomes is normal. That is a good thing believe it or not. Imagine if when your child tried to walk, then fell, got hurt and then quit trying because the outcome was crappy the first try. Keep that in mind when your child does something, has a bad outcome, then does it again and you wonder "why". It's a function of them sorting out if it's really not a good thing to do or if it's merely something they haven't yet mastered how to do it.
Back to lacking the ability to predict well, that is in line with warnings. Warning a child of what may happen, in any situation is really your choice. You may opt to warn your son walking on bumpy rocks is prone to tripping and tell him to "be careful", or you may be the sort hat prefers to let him take those risks and trust him to handle the fall and learn from it. Neither is really a "wrong" approach, it's just different and in parenting, some issues are okay for mom and dad to handle differently. This isn't a major divide on what your child is permitted to do (like perhaps if she let's him jump on furniture but you do not), this is a minor difference in approach to handling the same rules.
My spouse and I are even further apart in approaches than this often. I am more the sort to tell small kids what I want to see. Instead of asking them not to do something, I prefer to tell them what I do want them to do. My reasoning is that I get a better response. I think toddlers are terrible at figuring out what we want and constantly telling them what we do not want doesn't tell them what we prefer to see. So instead of asking them not to sit on the baby, I may ask them to sit on the floor next to baby and be gentle, and then go over and demonstrate what I mean. If they are being rough on a toy I may just remove it (without warning) and offer something else that is more suitable to the roughness they are seeming to want to display. If they start tossing wood blocks I may intercede and say that if we want to throw, we need to find soft things so we avoid breaking anything or hurting anyone. Then I tell them we need to hurry and pick up these blocks so we can get out the soft toys.
The other reason for my approach is that teaching is about showing children what we want. If they are learning ABCs and get it wrong, we don't tell them what is wrong thinking that will fix it (you missed K pal and ellamennopee is actually 5 letters you need to enunciate), and then ask them to say it right. We go over it with them and walk them through the order of letters again and accent that L, M, N, O, and P are separate. I see early behavior (when we mean typical situations) as the same. You walk them through what you want versus focusing on what they shouldn't be doing. There are literally a million things you do not want your 2 year old to do. You don't want them to hurt animals, be rough to babies, hit other little ones, spit on the table, throw food, on and on. I imagine that it is frustrating while exploring your world, your body, your constantly changing abilities, to be constantly told you are wrong, to stop, to do this or that. That is also a reason. I avoid as many negative interactions as I can because it seems to also reduce friction and stress the toddler is experiencing. I generally can get very good results (at least as good as any "no" will get you) while having less push back and upset from the child.
That alllll said. The TL:DR is that I think BOTH approaches sound fine and like you are both involved, engaged parents and if you intercede when unacceptable behaviors happen, the type you describe are going to wane with age (and then you have new issues/behaviors based on new situations with older ages that replace them, such is parenting).
