Hiya Cobber,
I wasn't going to post about trips and liabilities etc but as the subject is out I gotta say I agree with Silver. There is a need to be a tad careful. There is an arguable difference between texts or phone calls between individuals known to each other and open invitations.
Uuuummmm I'll try and explain it like this... you are going fishing.
You ring your mates who you know and ask them to come along
or
You can pop an ad in the local paper which has published several letters (posts) from you in the fishing section and has even asked for your opinions on tackle tests (anyone running 34 inch Gobbledock ATZ's, what are they like?) so many readers have already formed opinions on your experience and ability to catch 10 kilo flathead.
The deal is that 999 times out of a 1000 a friendly outing will end the way it started with a heap of gratitude from the invitees. It is the 1 in 1000 that you need to have covered your ass (and donkey and mule)
Clubs do that by Insurance and Rules.
Individuals have to do it by using good judgement and a taddy bit of luck.