I'm working as part of a forensic research group and honestly, this has all the pitfalls of so many other failed attempts of forensic analysis.
Something that immediately comes to mind is the accuracy of DNA identification from the most trace amounts means you get cases like this (
https://californiainnocenceproject.org/2013/06/how-an-innocent-mans-dna-was-found-at-a-crime-scene/) where they've locked someone up because he was in the ambulance before the victim.
This level of data collection blurs the lines so badly when you're unable to limit it to one person at the ISP level.
Say for example your mates porns habits are a little "risqué" but you let him connect to your WiFi. Say he opens his phone and it happens to be the last tab he opened but closes it immediately and carries on showing you the YouTube video you wanted to see.
Boom, hard evidence that you, the account owner, now watch ILLEGAL (other new bill) porn.
Children in the home? Fab, they learn about extremists and the dark web on the news. Have a wee google to find out what it is while you fire up your legitimate VPN to connect to work.
Boom, you searched about the dark web and then connected to a VPN.
It's easy to assume "innocent until proven guilty" but if "your" illegal porn browsing habits get leaked attached to your name (because thats literally how it will be recorded) will that effect your employability? I can't honestly say it would, but you cant honestly say it wouldn't.
Again, it might be straightforward to explain away your internet searches about extremism if you haven a productive and open relationship with your children while they're young, but for that to continue into adolescence without waivering is another matter.
This has disaster written all over it.