Jim beat me to the punch, so I will add, land mines and other unexploded ordinance... and also advise those who believe that Travellers are dirty, to go to well regulated halting sites which have trash pick up, no sense in picking it off the ground if no lorry ever comes to take it away... and go to such places as Murphy Village, a Traveller settlement here in the US, and you will find lovely homes, manicured lawns, and unlike, say, New York, folks don't drop wrappers on the ground - the place is imaculate.
As to "scrounging". Romany people and Travellers invented recycling.
When settled people recycle, they do so with huge companies, which add great cost to the whole process and they are considered the saviors of the environment, where the constant, reworking of cast aside stuff by Travellers is much more the way nature works, and is a much more ecconomical way of doing things in the end... no big corportate saleries to get paid for the idea of turning an old TV antena into a low=D whistle, etc.
By the way, Paddy Keenan once quipped to me, that if he knew how much Low D wistles would some day cost, he would have kept making them out of TV antenas rather than learning the pipes, and he'd be a rich man today.
Best to all
Lorcan