You're overthinking it a bit, and it'll likely be no problem at all.
As per the product description, they're airport safe. So you have two possible options, depending on what the airport uses.
- metal detector - according to the product, it won't go detect them anyway. So you're through and happy.
- t-wave detectors might show it, but for example, two nights ago I was shown my scan in the t-wave and it showed liquid around my chest (I was sweating from carrying a backpack), but didn't show my belt. So even then you're probably fine.
Worst case is that they detect some amount of metal. They'll either ask you to remove your 'belt' or whatever you might have. This happens so often it's ridiculously routine for them. You could either remove them then and rescan, or they'll request a patdown instead. It usually happens within yards of the detector, so your daughter will still be close by, and takes seconds.
I suppose worst case they somehow get it into their head even if you show them, that you're a risk for some weird reason - at which point you might get taken into a room to remove them, but even then they're not going to separate you from your family. My aunt was recently taken aside in an airport, and her husband was allowed in with her.
But realistically, assuming the suspenders do what they claim and don't set off anything, you're going to pass through in seconds and be on your way to a coffee at the gate :)
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