I think with aluminium domes, you do have the problem of the metal work-hardening and/or stretching along the crease and I doubt it would be possible to pop it back fully into place unless it’s a very shallow dent. But plastic should be fine in that regard.
Best
David
Buy new tweeter (s) send the bill to the owners of the little ankle biters 
Put my hifi away when my kids learnt to crawl and had to wait until the youngest was 6 before I got it out again
As a parent, my HiFi also took a back seat for the first 8 years, as you dont have the time to enjoy it, but now being a grandparent I think its OK to have both if you can manage it
I managed to enjoy my hifi throughout children growing up - and wouldn’t have had it any other way. First child spent many hours sitting in the pulled-out drawer of a desk while I worked from home, right by my side music on as normal. As toddlers they were often in the music lounge playing on the floor while I listened to music, or played with them. But after the cartridge incident I put the system in a cupboard with child-proof catch. The speakers were never an issue: immovable monoliths, grill cloth hiding the drivers, and would have taken some serious prodding to have been damaged.
I guess working from home gives you more time, but my work at the time involved a 1.5 hour journey, 8 hour day, 1.5 hour journey, so time I was home, there was a little free time with my daughter, and was often food then bed. Also didn’t help that she didn’t sleep all the way through until 4. Music listening moved to the car instead, and I did upgrade the Head unit, and speakers and an added amp 
I would never allow music to take a back seat, and I certainly believe that children are never too young to enjoy it (even though their taste will be different to yours). So the Hifi stayed put for us, as,of course, did the loudspeaker grilles. Sure, there were a couple of minor ‘incidents’ but the sooner kids understand what the gear is for, the sooner they start to use it properly instead of abusing it.
My working at home when the first was a baby was from about 7 or 8pm to midnight after about about hours in the workplace, most evenings. With my wife working evenings I was sole childcare in the evening - hence the desk drawer! Later when they were toddlers I managed to play for about an hour a day.
Put grandkids in at 50g’s that will put paid to anymore misbehaviour 
LOL. The tweeters or grandson? 
Tweeters of course!
Make the grandkids wear boxing gloves.
I find if I wear the boxing gloves and box them round the ears if they go near has a good effect.
Balanced retaliation. Smash his lego castle.
Not the same: the Lego can be rebuilt. To make the point you’d have to damage something in such a way that it is not repairable, and remains visible as a daily reminder!
But of course discussing that instead of teaching tit-for-tat would be better, if the child is old enough to understand. Whether it would work is another matter…
Another option: a tether like a goat in a field, keeping them out of reach of delicate things.
That reminds me that we had to resort to putting one child on a lead when out walking anywhere except deserted wide open space, as he was adept in disappearing within seconds of releasing his hand for any reason. (That was before you could get loss-of-proximity alarms to warn when that happens.)
Hmm… Having kept goats I can say with absolute conviction that a goat can out think any human when it comes to keeping them away from delicate things. 
Better not have goats in the listening room, then!
