if any race's whole fleet gets snagged inside a viral field, something went wrong long before.
If I have analyzed the situation to a point where I am confident in all possible outcomes, I might allow part of my fleet to be caught, however, I would be under mine cover, and would have tiered battlegroups just outside of 50 lys, but inside 81, and a 2nd one behind that for good measure. If the bot wants to move the viral field, the snagged ships get to move that turn, all my other battlegroups get to move and to protect the precious cybernaut the bots have to accept the right side disadvantage
the whole thing gets even more complex when planet cover is available and if allies are involved
in some cases I'd even go so far as to bait out the viral field if it allows me to gain a foothold somewhere else. To give an example: The bot needs bases to surrender the ships that are set to VRF. The bot needs loads of fuel to tow my heavy carriers. The bot needs clans to build bases. If the only planet in range is amorph, I personally reduced them to - 80 HP, he only has some golems and cats paws, all are kind of low on fuel, and I know that not a drop of fuel is to be found within 200 lys, he can snag me all he wants, the worst I can do is to trade carriers when he gets bored of keeping me in the field
I guess it boils down to: Scouting, scouting, scouting, Information, information, information. Don't pick a fight you can't win
edit: this is not theorycrafting, I have engaged Robot fleets that had cybernauts. Most of them think it's the invincible thing you make it as well, then they run into a scenario where the best outcome for them is a big carrier fight if they advance and lo and behold, they choose to not push the issue
Wirklich reich ist, wer mehr | Truly rich is, who holds
Träume in seiner Seele hat, | more dreams in his soul
als die Realität zerstören kann.| than reality can destroy.