Its not necessarily 'reckless'.
More 'pointless'. Why do you need to turn so steeply? Passengers in general won't enjoy it and you're erroding safety margins for no reason. What kind of ground feature requires such a steep angle of bank?
45 deg = 1.41g = Vs + 20%
If you're sightseeing, you've probably slowed it down to help people see things. You've eroded this safety margin by a further 20%. This might be fine when everything works perfectly. What if something doesn't? You overbank slightly, you get a decent gust. What if you need to turn more steeply due reason x?
In my personal opinion, decision making is about maximizing options, and by doing something like this, you are reducing them for no reason at all.
I reiterate though that I wouldn't call it 'reckless'. Just unnecessary. All the above is my personal opinion only.