Ducking under is OK
I certainly concur with JW411 that ducking under the 3deg approach path is a very big no-no.
To fine-tune this point, if one decides to do so or it is condoned at one's carrier, one must know one's aircraft and the runway.
One never, ever ducks under with a wide body due to gear clearances at the threshold - THAT is a no-no. If one is feeling the need to do so because one has even slight doubts about stopping distances, redo the actual landing distance calculations using all applicable factors in the charts, (which normally do take reverse into consideration, at least on the Boeing).
If it is close, one should
not be there in the first place. Don't do the approach, period. How one then resolves that, (divert, different runway, hold), is a PIC decision.
With smaller transports, (B737/A320, etc) one may make a decision to do so if one knows the airport and one's clearances and knows what a displacement of say a half-dot low means in actual height above the threshold, (a dot low at the threshold is a big no-no even though it can be technically done).
In those rare situations where one diverges from SOPs, one must think, "Now is the 30" I have in hand, which I may wish I had, 45" from now..."
There is simply no percentage in hitting a light or worse, just to satisfy your passengers' need to get to their destination. I should think that very few companies these days will question the resulting diversion if that's what it ends up being.