The GAA has warned fans who fork out hundreds on tickets from touts for this weekend's All-Ireland football final that they run the risk of being refused entry to Croke Park.
The alarming advice was issued to supporters after dozens of tickets for the Cork-Kerry clash destined for clubs and county boards were advertised for sale on the internet.
In a further clampdown on touts using the All-Ireland to make money, ticketholders who auction seats will be blacklisted by the GAA and have their allocations terminated.
The strict rules are the toughest any organisation has brought in to stop touts.
One pair of premium level seats are being offered online for more than €1,700.
The GAA said tickets not sourced officially are now considered stolen and using new electronic security tags they will be identified at the gates and holders refused entry.
More than 20 tickets for the Cusack and Hogan stands, Hill 16 and even premium level are for sale on internet auction room ebay with prices ranging from €350 for one to €600 a pair and on to more than €1,700 for the premium section.
A second website adpost.com is also offering tickets while gaelicfootballtickets.com is encouraging fans to swap tickets through its online service.
"The GAA has stated that a small number of tickets for Sunday's Bank of Ireland All Ireland Football final between Kerry and Cork have been reported as not reaching their destination and that these tickets are now presumed stolen," the GAA said today.
"With the new security ticket system being used for the finals these tickets will be nullified and will not be accepted by the computer scanning system now in operation for Croke Park.
"The Association have asked supporters to note that holders of tickets which have been reported as lost or stolen will not therefore gain admission."
Fans were warned to only buy tickets from clubs or county boards. The GAA said it has been in touch with ticketing websites warning webmasters the tickets could be worthless.
Sellers were also threatened with having contracts for tickets terminated.
"Holders of long term tickets who place their tickets for sale on such forums will have the remainder of their contracts bought out by the GAA and their term agreements annulled," the Association added.