Why can't Captain Kirk get a mulligan?

[Elok]

So they beam down to the planet: Kirk, McCoy, Spock, and Warrant Officer McSweeney.  Something horrible happens and McSweeney dies.  The others use their phasers on whatever killed McSweeney, or otherwise stabilize the situation.  Then Kirk says, "Hey, Scotty, McSweeney bought it again.  Can I get a mulligan here?"  Scotty swears picturesquely under his breath, digs through the transporter log archives (he may have it bookmarked, given how often this happens), and a shimmer appears over McSweeney's corpse.  A few seconds later McSweeney is regenerated as an exact copy of the iteration the transporter made of him when he first beamed down.  All he's missing is the last half hour or so.  They can fill him in.
I know why this doesn't happen: it would destroy all dramatic tension and raise further, still more troubling questions.  But I'm sure it's been asked many times over the years.  Is there a canon or accepted in-universe reason why they can't use the transporter that way?  The only limitation I can think of is memory usage, that the complete transporter map of a person is too big to hold onto outside of RAM or something.

[Lorizael]

Yeah. There is no log that holds the person. The information for a person is stored in a "pattern buffer" that destabilizes after some time/when there's space weather/when the deflector dish is being rerouted through the EPS conduits to divert secondary power to the phaser array...

[Buster's Uncle]

Maybe it's illegal.   Seriously; where's the end of it once you can do stuff like that?

[Geo]

Maybe it's illegal.   Seriously; where's the end of it once you can do stuff like that?

Living the last day of your life again forever!

[Elok]

Maybe it's illegal.   Seriously; where's the end of it once you can do stuff like that?

So ban it.  What's the penalty?  Death?  I don't think The Federation is allowed to do that, and anyway, "don't come back from the dead or I kill you" is a pretty sad deterrent.
Lori, I can't even tell if you're making that up or if it's official ST Lore.

[Lorizael]

The minimal fact of there being an unreliable, temporary pattern buffer is canon. The rest... /me shrugs

[E_T]

Although it was recently done very well in Doctor Who (Heaven Sent), well sort of...

[E_T]

Beside, the Redshirts almost always die... typically in a horrible fashion...

[E_T]

Although, I do recall one story where a transporter was used as a sort of long term lifeboat for a few individuals.  Not all of them made it (had still degraded over time and were "lost").  IIRC, the pattern buffer was put in some sort of maintenance loop that cause it to keep refreshing the buffer contents, instead of having them re-materialize on the platform.  Whomever it was, had survived in the buffer for a very, very long time.

[ColdWizard]

TNG episode "Relics", wherein Scotty survived 75 years in a jury-rigged buffer. The other crew member degraded.

[E_T]

Transporter clones...

[Geo]

Beside, the Redshirts almost always die... typically in a horrible fashion...

Not in TNG!

[E_T]

One of the reason TNG wasn't as fun...  Still good overall, but...

[Elok]

They also didn't have things like the transporter malfunctioning and splitting Kirk into good and evil halves.  Darn that busted evil filter.

[Lorizael]

Apparently redshirts weren't the most likely to kick the bucket in TOS...

https://www.youtube.com/watch?v=GRp92HXDlgY&feature=youtu.be&t=1m50s

(hopefully that skips you to 1 minute, 50 seconds)