a family group of mature boar, sows and piglets is quite noticeable.
rooting, nesting, wandering about with squiggly piglets etc all have strong sign or direct observation
i would be aware it (or they)may be around but not very worried, they will avoid you if at all possible (or steal your lunch) and are only dangerous if they see you as a threat, if so back off politely telling them you will go that way so they can continue doing piggy things
a few apples and a night in a tree with a night sight is a viable option if they do seem to be a problem
We do have the option of a trail cam if we think they have been in our bit of the wood. No sign of rooting that I have seen, but do have dogs and badgers digging, so may have assumed it was them. Hopefully just a lone one passing through.
Yes, I would expect them to be on fruit for sugar at this time of year. I was surprised to see hornets on the grapes a little while ago; of course they could have been taking insects that were on the sugar, but I didn't have my glasses on, so wouldn't have been able to see very tiny insects.