As far as I can tell, if (1==1) { } is being used as an alternative to commenting out the lines. While this may provide a simple way to skip a block of code by changing a single character, there appears to be a performance detriment:

#!/usr/bin/perl -w use strict; if (1==1) { 1; } [download]	$ perl -MO=Deparse equal BEGIN { $^W = 1; } use strict 'refs'; do { '???': }; [download]
#!/usr/bin/perl -w use strict; if (0==1) { 1; } [download]	$ perl -MO=Deparse unequal BEGIN { $^W = 1; } use strict 'refs'; do { '???' }; [download]
#!/usr/bin/perl -w use strict; if (1==0) { 1; } [download]	$ perl -MO=Deparse unequal2 BEGIN { $^W = 1; } use strict 'refs'; do { '???' }; [download]

#!/usr/bin/perl -w use strict; 1; [download]	$ perl -MO=Deparse uncommented BEGIN { $^W = 1; } use strict 'refs'; '???': [download]
#!/usr/bin/perl -w use strict; # 1; [download]	$ perl -MO=Deparse commented BEGIN { $^W = 1; } [download]

UPDATE: Added the if (1==1) { } corollary