To be a bit more abstract, just because something is "random" does not mean it cannot be characterized with a distribution, expected life, etc.
The philosophical/mathematical effort at quantifying randomness has been called "The Taming of Chance".
After all - drawing left to right top to bottom, from the FBI most wanted list as of shortly before this post - we have:
1) Kidnap and murder of a little girl
2) Beating and raping a woman in march 1998
- Alleged beating, raping and murder of a second woman while out on bail
3) Alleged Shooting and killing an armoured car driver outside a movie theatre and making off with the money.
4) 1987 escape from prison followed by a 1991 murder and subsequent escape from prison in Mexico after being arrested for drug trafficking
5) Racketeering, conspiracy to launder money instruments, conspiracy to have [assorted drugs]
6) Killing his wife and two children, then burning his house down.
These aren't exactly Mensa candidates.
You have an isolated group of people: how surprising is it that a social animal develops its own culture distinct from the larger population that they are forcibly segregated from?
This social phenomena has persisted for a long time: Is the length of the history indicative of some quality unique to members of the subculture or is it one of the necessary byproducts of existence of a legal system?
Everything. The subculture is a mechanism by which an ethic of existence (or survival in this case) is propagated. Techniques, warning signs, all of these things. In this case, it is indeed unique to these people in that the techniques may only be useful when you are on the lam.
In fact, the uniqueness of this situation seems to be exactly what you are trying to handwave away as "it's own culture distinct," but you are ignoring the word itself: subculture exists not separate from other cultures, but as a part of them, and as a part of larger ones, such as the legal system. The legal system itself has a multitude of cultures: correctional officers have an interdependency with the judiciary, but you wouldn't say that they operate by the same terms. Judges and court reporters don't usually go to the same parties, and thus the culture of incarceration and evasion of the law also operate on their own terms and by the terms of the legal system at large. As a case in point, that is.
Preparation and profile are not "simple," nor are they black and white, as what those things actually mean is massively different from one situation to the next, criminal dealings or not. Characterizing them as something that either does or doesn't happen and does or doesn't entirely cancel the possibility of capture is not useful.