At Wizid, we occasionally receive requests for non-standard tyvek wristbands.
We have received requests for narrower tyvek wristbands around 12mm in width rather than the regular 19mm & 25mm widths.
These would need to be custom made & are really a false economy as the narrower bands would have a much smaller area of adhesive, which would make them much easier to remove & transfer.
If you are thinking this may be a cheap alternative wristband, you are running the risk of saving a minimum amount on each box of tyvek wristbands but losing revenue if your patrons leave your venue & then on sell to others at a discounted price, who then can enter your event.
This way both the entering & leaving patrons are cutting THEIR costs but you would be losing revenue, as the new patron would not be paying you for entry.
All tyvek wristbands have a tamper evident area designed to split & tear if someone tries to remove & transfer the wristband. It just stands to reason the wider the wristband, the harder it is to transfer & the better the security.