To me Col Brandon’s “ranging over town” (Ch. 31) does not imply anything nefarious. Rather Eliza & Friend, like Catherine & Isabella in NA, did normal Bath activities such as going to the pump room, shopping, walking and (perhaps) carriage rides alone with gentleman. There does not appear to be a general rule requiring chaperones for these sorts of (daytime?) outings because the second two are not censured for the lack of one. Perhaps “making what acquaintance they chose” refers to the fact men were introduced to ladies and Eliza & Friend accepted an introduction to Willoughby. If so, I doubt Col Brandon thought it was a foreseeable mistake on their part. This is just my opinion, I do not know exactly how Eliza & Friend spent their time or how they met Willoughby.

Is there any evidence Eliza & Friend were improperly introduced to Willoughby or any other men? An improper introduction and a person who turns out to be a nefarious character are not necessarily the same—Willoughby is certainly the later although I doubt he was the former. I think all that is required for propriety is that an introduction is made by a known respectable individual who is essentially vouching for the new person’s general respectability. This could be an acquaintance, friend or someone like “The master of the ceremonies” at the Lower Rooms—he properly introduces Henry to Catherin in NA as a respectable dance partner. In P&P Lizzy and sisters are respectably introduced to Wickham by their friend Mr. Denny. The presence of a chaperone does not seem to be required for the propriety of an introduction.

I just don’t see Col Brandon’s statement “while the girls were ranging over the town and making what acquaintance they chose” (Ch. 31) as proof of impropriety before things very obviously went wrong. Before Eliza went to Bath Col Brandon had been pleased with her conduct, he says “for two years I had every reason to be pleased with her situation” so it seems when he allowed her to go to Bath, “at her earnest desire” no less, her character and behavior was in no way troubling to him. However obviously something changed after Eliza arrived at Bath because she does very troubling things. She elopes with Willoughby, becomes his mistress and most likely extracted a promise from Friend of secrecy, all of which I am sure, she knew was improper. She also let Col Brandon worry about her for eight long months.

I think what happened was Eliza met Willoughby and he beguiled her into loving him for the specific purpose of seducing her into a sexual relationship. She is young, innocent, eager (Ch. 31) with a weaker understanding than Marianne (Ch. 44) and as such an easy conquest for Willoughby who is an accomplished liar and manipulator. Considering his dealings with other women I feel nearly certain Eliza believed Willoughby would do right by her. Willoughby acknowledges Eliza’s “situation and her character ought to have been respected by me” which suggests he saw the facets of her character and situation that he could take advantage of, knew that he shouldn’t but did so anyway simply because he was “thinking only of my own amusement, giving way to feelings which I had always been too much in the habit of indulging” (Ch. 44).

Of course Eliza had the choice to say no but I don’t think it would have been very easy since seduction by nature earns the victims trust, counters and overcomes objections and creates a bond between the seducer and the seduced. Willoughby had every advantage over Eliza in understanding, wordiness and situation and I am sure he used it against her just as he did against Elinor in Ch. 44. In Ch. 45 Elinor realizes she was persuaded to think better of Willoughby “rather in proportion, as she soon acknowledged within herself to his wishes than to his merits” so how realistic is it to think Eliza, who is no Elinor, would be less sensible of his influence from the much weaker position of being his object. Eliza and Willoughby are not on equal ground and that is why his responsibility far outweighs hers and of course he could, after all, just have passed on seducing her.