Single Crossovers with Insulafrog Turnouts

A question about how to correctly wire a single crossover made up of Peco Insulafrog turnouts came up over here as well, but it left me with a question.
 

I have a number of locations on my layout plan where I have the diverging routes (frog tracks/rails) mated up to one another back-to-back so to speak, ....

1) long turnouts in pairs forming a single crossover
2) long turnout paired with curved turnout forming a single crossover

I'm trying to determine my need for insulators between the pairs, in both cases,.... where they might be thrown correctly in unison,...and where they might be thrown accidentally against one another.

One cannot go wrong to supply insulated joiners at the frog end of every turnout. This avoids any issues caused by power routing via the points You can always add electrical feed wires after the turnout. However be careful in the case of crossovers. One must maintain the proper polarity Of both sides of the mainlines in order to avoid the creation of a ‘reversing’ issue.
DonV

I echo Don Vollrath's comment.

Let me further amplify Don's comment about adding insulated joiners at the frog end of every turnout.  As I build my new railroad, that is exactly what I am doing.  Electrically, you may not have to, but if you make a wiring mistake, problems are easily found.  You need joiners, whether they be insulated or metal, so why not avoid trouble?

Allan Gartner
Wiring For DCC