Great topic with lots of good advice.
I tend to agree the most with Trail Twister here.
Soaking the side rails is a great point and gorilla glue is great stuff too. I also have imbedded wire for support and took the easy road and just nailed sections, and honestly - you can't go overboard in frame contruction. It is a time verses return issue. But at the very least I always glue the frame pieces, eventhough as Finman said "the bees glue everywhere" there still an invunerable time where the frames are not yet drawn out and when mixing them with older (more built-up frames) you can get to prying in the wrong place and break the newer frames apart.
If you are always dealing with frames the same age and same exposure to the internal workings of the hive, you can fudge a little and NOT go overboard on strengthening the frames, but over the years we are always mixing and matching frames from hive to hive and there is often a trendous amount of propolis to deal with (especially if you don't inspect frequently) so I believe reinforcing the frames with glue and nails is the MINIMUM I would do.
Adding wire support is strictly a "Blow-out" prevention for extracting in cyntrifical spinners - and most motorized ones are built to do a fine job of NOT overly stressing the frames by winding up slowly and winding down slow too - but hand operated spinners can be rough, judging the right speed and working the frames from one direction to the other (not to forget improper load balancing) you can easily get the extractor hopping around and over RPM it and THAT is when you will blow-out the foundation.
I've wired many frames and when you are only dealing with a handful of bee supers to load with new frames, it's no biggy putting massive reinforcement into the frames - ideally, although many will argue that doing all the gluing and wiring is overkill, I still say that ideally if time is not an issue and if you assembly-line the whole process, going all-out is the way to go.
I really suggest glue and nails as a minimum and if you hand-spin the frames, you might think about wire reinforcing too. But it all boils down to how much life you expect to get from your frames. I always like to think that it is a one time investment, but we all know that isn't so. So spending the extra time to give each frame a long life span is worth the effort if you want the biggest bang for your buck.
I have a screen-door on my back porch which is now 8 years old. I put L-brackets in all corners (inside and out) and I put a heavy wire mesh on the bottom section to keep the neighbors cats from ripping at the screen and also stained and eurathaned the door. My screen door is as sturdy as the day I installed it. My neighbors bought the same door, didn't do anything to reinforce or protect it and it lasted one season, literally sagging to the point that it fell off the hinges. The cost of the door wasn't much, but the labor was a bit time consuming, but I believe I'll get another 5 years out of that door, so it really paid off in the long haul.
I'll add a photo of what soaking can really accomplish to illustrate a point later tonight. I have a wooden hand-crafted puzzle which uses soaking to accomplish a very neat illusion - again, look for the image later once I upload it.
Again, these are just my opinions, we have a lot of very valid opinions on this topic - it comes down to choice and maybe even experimentation - there is nothing wrong with doing one super one-way and another super another, then comparing them down the road. That may be the best of all solutions.