I agree with the notion of having more checks after events like the football and around Christmas when more people are likely to be over the limit - and especially the morning after when it's very easy to forget last night's 8 pints.
Guess what, there is far more driving under the influence in the summer than at Xmas.
Even prior to successive governments seasonal campaigns, remember the song "In the Summertime"
"....Go out for a drink and a drive...."
My fiancee and her daughter were killed by a driver 2.5 times the limit at 11:30 on a lovely summers morning after the £$"! had "just been out for a nice meal in a country pub" the night before.
As the law stands anybody can be tested on "reasonable grounds to suspect", after involvment in an RTC, or after commiting a moving traffic offence.
At the risk of stereotyping.....If I were a cop a white van, with the "idiot flags" the morning after a match would be prime cannon fodder under the reasonable suspicion ruling. How many of the folks you see in the crowded pub on match night are likely to have only had a couple then drive to work in a Merc and sit behind a desk all day?
{off me soapbox}