I've been bagging a few trigs recently but find a lot are in the middle
of fields.
Do people tend to not bother with those and go for the easier ones,
or is it a case of asking permission or "trespassing".
For most of us, I think its a mix of all of the above. Its worth reading the
logs of previous baggers to get a sense of where asking permission to visit
the trig may be necessary; for example where the trig is close to farm buildings
or where the landowner if known to be sensitive to unauthorised visits.
Regardless of permission, any visit should show respect for the farmer's livelihood,
e.g. leave gates as you find them, try to avoid climbing walls, follow paths/field
boundaries where possible, even if that lengthens the journey; avoid visits when
crops are growing, avoid damage such as making a hole in a hedge or fence.
In my experience, encounters with farmers are rare and most are tolerant of 'trespass'
if you explain politely why you happen to be on their land. But leave without argument
if asked to do so (theres always another day).
Be circumspect in openly publishing access details in a Trigpointing log where the
route taken might upset others - it isn't just baggers who may read it (and I'm guilty
of ignoring this advice).
In summary, by all means request access where you feel its appropriate.
But its often a case of EAFP - Easier to Ask for Forgiveness than Permission.