Anglophone military literature places much emphasis on surprise, and rightly so: Surprise is a huge lethality multiplier in combat. Air, sea and land.
There was even a time when the concept of surprise was interesting enough to distinguish between moral surprise and material surprise.
The classic counter to surprise is security; basically defensive reconnaissance by satellite forces (pickets or small teams moving in parallel to the protected force).
It is -as so often - possible to look at the same subject through a different lens, though. And a different lens may be very useful on this subject.
There's a German word - Gefechtsbereitschaft - for readiness for battle.
This is similarly far-ranging as "surprise". A force deployed in the field and moving forward can be expected to have maximum battle readiness against foes in front. Less of its potential strength is available for sudden contact on either flank. Even less is available for a sudden contact in the rear.
The same force - not deployed, but marching on a road or two - may have had a very low readiness for battle an hour earlier. And yet another hour earlier it was probably in bivouac, with some vehicles undergoing immobilizing repairs and much of the personnel at sleep. The readiness for battle at that time was marginal.
And that's the normal: Marginal readiness for battle. No force can maintain a high readiness at all times. A high readiness for battle is the exception, and "surprise" is about getting in contact with the enemy when the enemy is not ready for battle, while your forces are.
Gefechtsbereitschaft / readiness for battle provides a different lens, a different perspective on the issue because it looks at the own forces.
Now look at the standard recipe of security: Assuming your security effort is at a substantial distance (say, varying from 2-20 km), you're likely not able to maintain it without diverting a huge share of your forces to it. The circumference of a circle grows quickly with an increasing radius, after all. A thin security effort won't have much delaying effect.
Modern mechanised forces could push through such a distance within minutes if their leader suspects a great opportunity to surprise you.
It's in this light not a good idea to trust "security" much, or to look at the problem dominantly through the attacker's lens ("surprise"). Instead, your forces need at the very least the readiness to elude the enemy, as readying for meeting him in battle would be even more demanding - often demanding too much.
This in turn requires a lot of training. The breaking of camp within minutes into one of several possible directions (and in satisfactory order) takes much practice. You need to do it again and again, and you need to have the troops truly settled (maintaining and sleeping), so you cannot simply run ten such exercise alarms on a single day.
Now what do you think may be a rather neglected skill in an age in which large scale military manoeuvres involve computer screens more than actual units camping in the fields (and outside of permanent military training areas)?