That's not true. Many players have stated that they have done many tests out of competition ...
The list of out of competition tests for 2009 was leaked, and it was a joke. Barely 1 per week average out of competition tests for the entire top100.
....and you cannot lie about your whereabouts because an agent could get wherever you say you are within hours.
Sure you can. Testers turn up, guy isn't there, he gets one strike. The testers don't go phoning around, chasing people. Three strikes in 18 months, and you get a suspension.
This allows players to dope at certain offseason training times during the season: February, July, December. The chance of getting three strikes is minimal, cos there are barely any OOC tests at those times. According to the ITF, these were the men tested during those months last year:
Mathieu x2 (one missed test)
Simon x2 (both tests missed)
Nestor x2 (one missed test)
Kohlschreiber (missed test)
Koellerer (missed test)
That's it. The prime doping months of the year, nobody in the top5 was tested, only two top10 guys were tested, only six top100. Of those six, Haas and Mathieu were long term injured so it was pointless going to test them.
Also, none of the above included blood tests, nor EPO tests.
Basically: the sophistication and short life in the body of current drugs means nobody will ever be caught by the testing itself. Three strikes is the only weapon tennis authorities have, and the system as it is will never give anybody that three. At best it can hope to disrupt players and give them two strikes, they then take a year off the dope to let strike1 expire, and then go back on.
The system as it is looks like it was designed to catch nobody .... and even if they do catch people, it gets covered up, eg Agassi and the 42 who got caught on nandrolene in 2004 (only Rusedski was named, and the "contaminated supplements" ruse has been utterly debunked through testing).