Here is a Frank Stewart hand.
You, South hold, ♠K986 ♥KT7 ♦875 ♣KQ9
Both vulnerable, North dealt and opened 1C.
North East South West 1C Pass 1S Pass 2S Pass 3C Pass 3D Pass 3NT All Pass
Stewart characterized South's 3 clubs bid as "a bit bold," and 3NT as "living on the edge--or beyond."
I do consider South's bidding "bold" but not "edgy." I was taught to "bid to make," to freely bid contracts with a better than even chance of making.* (More to the point, I believe that Stewart was trained in that school as well.) Even so, South had 11 hcps opposite an opening hand. In subsequent bids, North had shown support for South's spades and a stopper in diamonds, and more than a bare minimum hand.
Dummy had (among other things) ♠AJx, ♥A, ♦A, enough make the contract if a spade finesse works. Given that the Q was "offside," Stewart showed a "hairaising" winning line that involved using the A of diamonds as "transportation" for a (successful) second club finesse.
Under IMP scoring, you will come out ahead if you bid and make contracts with a 40% chance of success when vulnerable, and a 50% chance when not vulnerable. Given this fact,
Is Stewart among only a few experts who would condemn South's bidding?
*This does not include sacrifice bids, where I have enough trumps to reasonably expect to lose less going down than allowing the opponents to have the contract.