5% is neither here nor there, who's gonna bother charging it? It's the (potential) cost of assuming credit risk that bothers me.
Charge-backs are few and far between, granted I did have One Kount who pulled it on me years back in the bookie game as was documented on here before, but in all the years he was the only one.
The Two main reasons that customers do not do charge-backs are;
1. Because the banks keep it very low key and do not advertise it at all and if you wish to do a charge-back then you will need to go through a mountain of paperwork and emails to get it, not like back in the day when I was caught out, back then you could just ring your bank and talk to someone.
2. If you do a charge-back then most likely you will get it the First time but the banks watch everything and every keystoke is noted, if a customer does it repeatedly with Taxi fares or online services then the bank won't be long closing their account.
Taxi fares in law are considered as Services provided and by law must be paid. Bookie debts are different, they are a gambling debt which is not enforceable by law.