How are the watchmen able to discover what Borachio has done? How much do they understand of what they have found?

The watchmen are only to see what they have found in the case of Borachio by luck more than judgement, this is shown in the line 'a goes up and down like a gentlemen; I remember his name'. This shows the watchman was lucky to hear anything after this because Borachio could hear the watchman speak, this is shown in the line 'Didst thou not hear somebody?'. This shows the watchmen at the time were portrayed to be idiotic, as they were almost caught out in trying to catch a criminal. Camille Wells Slights says in a play 'language is power' this begs the question that do the watchmen actually know anything, as it seems that they have no power whatsoever in this scene, due to the fact that they are hiding from the men they potentially want to capture. At the time for the watchmen to be able to arrest Borachio and Conrade would almost be inaccurate historically as even Dogberry said 'it is an offence to stay a man against his will' this means that in Dogberrys eyes it is not acceptable to arrest a man who doesn't want to be arrested, moreover meaning there is overall no point in Dogberry or the watchmen being there. Overall, I believe the watchman knew that Borachio and Conrade were up to not good just not to the extent they were, I believe this as throughout Act 3 Scene 3 they have seemingly had no idea what to do, so why should now be any different. This outlines the fact that Shakespeare was trying to make as in watchmen at the time were not capable to look after the country, but most importantly they were not at all educated men.