I wonder if not pursuing these claims would jeopardize their ability to pursue legitimate rip-off artists; the appearance of being prejudicial in what they want to pursue?
For example, what if the small Beaver's Mini Mart decides to create a chain of large size Beaver's Mega Marts with a similar size, format, and logo to that of Buc-ee's? Buc-ee's could sue, but their case would be complicated by their prior toleration of Beaver's name, logo, and operation of smaller format gas and go markets.
To prevent that risk, Buc-ee's best strategy is to sue now. The usual practice is to then agree to a settlement that restricts the smaller operation from ever infringing Buc-ee's trademark. That way, if the small operator ever goes rogue, Buc-ee's can go to court and sue to enforce the terms of the settlement agreement.