I would guess that it's due to liability issues these days, it's NOT what it used to be everywhere in public now, that's for sure...
I'm sure others can fill you in on the Commonwealth's stand regarding this type of policy. I know that most places now wherever you go won't hesitate any more with this issue of ID'g & all that.
TD Banknorth Garden
"Alcohol Policy:
Alcohol is served at most TD Banknorth Garden events. Garden staff is trained in responsible alcohol service management. To purchase alcoholic beverages, a patron must present a valid MA driver's license, MA liquor ID, passport or military ID, which indicates the patron to be a least 21 years of age (MA ID cards, duplicate licenses, expired licenses, damaged licenses and driver's licenses, which do not have photos, will not be accepted).
Out of state licenses are acceptable only if the patron is at least 25 years of age and another form of identification (e.g., credit card) will be required if the patron is between 25 and 30 years of age. Any patron in the possession of alcoholic beverages on premises may be requested to produce identification, which must satisfy the foregoing requirements. No refunds will be offered for confiscated alcoholic beverages.
Any patron who presents false identification or who passes alcohol to a minor may be subject to eviction and arrest. We will not serve more than two alcoholic beverages to a patron at one time and we reserve the right to limit service to one drink per patron.
Our alcohol service will end at least one hour prior to the scheduled end of an event. We reserve the right to discontinue the sale of alcohol at any time.
We will not serve any patron whom we believe to be intoxicated.
Alcoholic beverages may not be taken into or removed from these premises. Any patron in the possession of alcoholic beverages not obtained on premises will be subject to eviction.
Intoxicated Guests
TD Banknorth Garden reserves the right to deny entry to intoxicated guests. Any intoxicated guests causing a disturbance during an event will be asked to leave the facility and may be subject to arrest."