It is not time or cost efficient for large chariites to enter into written, signed agreements with commercial participators who expect to raise £1,000 or less and consequently they have to refuse permission for lots of small businesses to raise money.
This excludes lots of people (e.g. those who don't have wealthy social networks or the resources, time, inclination or ability to organise other types of fundraising event or those who don't have sufficient spare cash to make straight forward donationss) from supporting causes that are close to their hearts.
Adding a de minimis for commercial participators would make it easier for small businesses to be part of big society. It would increase the amount of money raised for charity and create and encourage lifelong supporters for charities. Such small businesses are often at the heart of their communities and are usually well placed and highly motivated to encourage other people to support the charity.
Imagine Beryl the Baker. Her sister has just died of leukeamia and Beryl currently raises money for leukemia charities which are very appreciative of her efforts, even though she sends them 'only' a few hundred pounds a year. However, in the recession her circumstances change. She has to move to a new town where she doesn't know anyone so she can't organise fundraising social events, she doesn't have the spare cash to make a donation of her own money and she is too frail to take part in the charity's own events. She decides to raise money by donating 10p for every cake she sells during November. She expects to raise £300. She contacts her favourite charity full of enthusiasm and but they say that the amount that she will raise is too small for it to be worth their while enterring into an agreement with her and she isn't allowed to carry out her plan without an agreement. She is is shocked and hurt and decides to stop supporting the charity and writes it out of her will. this outcome is bad for her, bad for the charity and bad for society. Such stories could be prevented by adding a de minimis to this requirement.