Probably the same people who open there waste tanks any where or dump toilet waste when wild camping..But cannot believe if this a major problem that dealers don't check vans as they are brought in,and refuse to accept them.

Don't know how big the problem is to dealers but last two vans we traded in were not looked at before we left with our new vehicle (at Tyne Valley Motorhomes and Todds of Preston) so cassette could have been full.
But to be honest I posted 'cos it was funny, rather than me feeling sorry for dealers...... maybe I'll get a discount next trade in?