You've met them, these canvassers. At a show... in the high street...
They work on commission and their sole purpose is to get phone numbers. The owners of these numbers are then harangued into buying time-shares or similar - 'holiday clubs' seem to be the flavour of the month.
The process of getting that all-important phone number has evolved into something quite sophisticated. The target might find that a free holiday has been won by just being there at the right time (what amazing luck!). Marginally more tediously, the target might tear open a coupon to discover - surprise, surprise! - the three symbols line up and they've won a holiday. Whichever, the target gives up their contact details and is then phoned incessantly until they agree to attend a two-hour 'presentation' to receive their prize. At the same 'presentation' they will also be pressurised into buying a time-share or 'holiday club' membership.
The free holiday, by the way, will be next to useless. It's accommodation-only (ie, excludes the cost of flights) and at a place and a time of year that are completely unsuitable. These sales people aren't stupid, you know.
In their single-minded quest for phone numbers - and commission - the canvassers have absolutely no respect for anyone or anything, invading the space of both traders and visitors in an effort to chase down unsuspecting victims. ('Chase' being the operative word - I've seen targets actually being chased down aisles for that all-important phone number!) Of course, many visitors already know the score and see the canvassers on the prowl with their clip-boards. In an attempt to avoid them the visitors speed up and take a wide detour, or perhaps even turn around. Adjacent traders have an altogether miserable time. Ask the canvassers to show a degree of restraint and you'll be met with, at best, blank looks and, at worst, abuse.
Many of the more responsible shows are now recognising the nuisance and distress caused to both traders and the public and are banning time-share/holiday club exhibitors.