Concerned in the sense that it'd be awkward for a while & I don't want that. But that's more to do with if they happened to walk in on me mid-jerking. But to recant a tale from the past:

When I was about 14, my Dad had to do something with the computer because it was getting viruses. I thought I was very careful with my history. Turns out I knew very little about PCs at the time & he managed to find an entire list of websites I had been looking at. Some of the stuff was real embarrassing too (like gay, transgender, old granny stuff. If you're into that then whatever, but I was 14, I was mainly curious as to what any of that stuff looked like & it's real embarrassing for any teenage boy to be caught with).

So I was sat down & talked to by both parents. My mother was absolutely disgusted with me ("I can't believe you've done this"). Weeks later I was caught again with it by my Dad, but he decided not to tell my mother this time. But for a few weeks after he'd jab at some of my friends ("So do you be watching that porn business as well, aye?").

It was an incredibly embarrassing time in my life. For the next few years I figured out how to properly use computers, but I was still wary of using websites so I'd use even the most basic of shit to try jerk to. It could be a magazine that showed a nip slip, an underwear catalogue, it didn't matter - I just couldn't deal with the shaming from my Dad. At least now I've had my own laptop for the last 7 years.

That's a big reason why I've never discussed anything about my relationships or sex with my parents. I was never even given the 'talk' from my father. Even now at 25 I couldn't deal with being caught again. But I'll be moving out soon any way, so I'll not have to worry about it.