No, actually it doesn't happen.
A modern DA revolver can only fire if the trigger is physically pulled, OR if the loaded gun is tossed into a fire.
I once saw a test to prove this.
A S&W revolver was loaded with a blank cartridge under the hammer and a mallet was used to beat on the hammer.
Eventually the hammer snapped off.
The cartridge never fired.
The hammer blocking, rebounding design was designed in the 1890's. Colt perfected it with their "Positive" hammer block in the early 1900's, S&W perfected theirs in 1945.
Colt did an update of the old Iver Johnson "Hammer the Hammer" transfer bar action in 1969, and most all revolvers designed since use a version of Colt's transfer bar action.
Neither a rebounding hammer/hammer block, or a transfer bar action can fire no matter how hard the hammer is struck, as long as the action hasn't been tampered with.